A New CPW-Fed Semicircular Inverted Triangular Shaped Antenna Based on Mixed-Alternate Approach for 5G Millimeter-Wave Wireless Applications

This paper presents the design and development of a new semicircular inverted triangular shaped antenna for 5G millimeter-wave wireless applications. An alternate-mixed approach based on cavity, slots and loaded stubs is employed in the designed antenna lattice. The suggested antenna structure is formed by a radiator, partial defected metal ground plane and a 50 Ω coplanar waveguide. The proposed antenna resonated at multiple frequencies by the setting up of the proper dimensions and locations of the rectangles, elliptical cut slots and cavity stubs. Furthermore, a parametric analysis is carried out to examine the antenna’s effectiveness and impedance-matching controls. The proposed structure is realized on the low-cost RT/Duroid Rogers RO3010™ laminate with an overall small size of 1.381λ0 × 1.08λ0 × 0.098λ0, where λ0 represents the wavelength corresponding to the minimum edge frequency of the 23 GHz at 10 dB impedance bandwidth of the antenna. The antenna’s key characteristics in terms of bandwidth, gain, radiation patterns and current distribution have been investigated. The antenna exhibits high performance, including an impedance bandwidth of 19 GHz ranging from 23 GHz to 42 GHz, results in 58.46% wider relative bandwidth calculated at 10 dB scaled return loss, a peak realized gain of 6.75 dBi, optimal radiation efficiency of 89%, stable omnidirectional-shaped radiation patterns and robust current distribution across the antenna structure at multiple resonances. The designed antenna has been fabricated and simulation experiments evaluated its performance. The results demonstrate that the antenna is appropriate and can be well integrated into 5G millimeter-wave wireless communication systems.


Introduction
Recently, massive development in 5G networks have been at the forefront of research. The millimeter-Wave (mm-Wave) communication spectrum has received much attention. There has been a great deal of interest focused on effective antenna designs which offer higher gains and broader bandwidth for use in a future 5G mm-Wave system [1]. High frequencies in the mm-Wave range are the only examples with this capability, hence upgraded spectrum utilization will be necessary to cover the specific range of frequencies [2]. A spectrum utilization at frequencies greater than 24 GHz has been suggested by the World Radio Communication (WRC) conference and recommendations sent to International Telecommunication Union Radio (ITU-R) to nominate potential frequency bands [2]. UP to this point, frequency bands between 24.25 and 86 GHz have been reported in the literature [3]. However, 28 GHz and 38 GHz frequency bands are the best choice for modern 5G communication technologies [4]. arms were connected with the central part of the flame structure to achieve multiple resonances at the desired band of interest. In addition, a broadband symmetrical E-shaped patch with a multimode resonance antenna has been presented in [45]. The reported antenna consists of an intricate structure with a broad BW ranging from 31.5-50 GHz and exhibited satisfactory performance. However, the work reported high fabrication processes and complicated assembly. Hence, it is concluded from the recently published research that the reported antennae have complex geometries, high fabrication processes, larger dimensions, and most provided reasonable performance across a short frequency range. Furthermore, it is also noted that there is trade-off between antenna key features and compact dimensions.
The main contributions of the paper are given as follows: • An alternate-mixed approach based on cavity, slots and loaded stubs is proposed which results in reducing the antenna's design and fabrication complexity.

•
The suggested antenna structure validates a new semicircular inverted triangularshaped cavity-based antenna with a small size of 1.381λ 0 × 1.08λ 0 × 0.098λ 0 , which develops a more effective model.

•
The antenna exhibits far-field stable omnidirectional-shaped radiation pattern, broad fractional BW of 58.46% at required frequencies, a peak realized gain of 6.75 dBi and optimal radiation efficiency better than 89% over the operating band. To the author's best knowledge, the results are more effective than the rest of the previously researched antenna designs. • Finally, the antenna performance is evaluated and analyzed alongside recently published state-of-the-art works.
The paper suggests a new antenna design to achieve broadband performance for 5G mm-Wave wireless applications. A semicircular inverted triangular shaped antenna is formed with a radiator, PDMGP and a 50 Ω CPW. An alternate-mixed approach is employed to achieve optimal results. The proposed antenna structure is designed on a low-cost Rogers RT/Duroid 3010 TM laminate. The antenna exhibited 19 GHz bandwidth (BW) resulting in 58.46% relative impedance BW at 10 dB return loss. Moreover, the antenna obtained highperformance characteristics, including high realized gain 6.75 dBi, strong surface current distribution and stable far-field elevation (E) and azimuth (H) plane patterns. Moreover, an elliptical cavity-based stub loaded element influences the far-field radiation pattern. A high-frequency structure simulator (HFSS 17.2) full wave electromagnetic solver based on the finite element method (FEM) was used in the designing and simulation process. The antenna results have been verified in a real time environment. The simulation and measurement results coincide well each other. The proposed antenna is highly suitable for cutting-edge technology applications and may be integrated into modern 5G mm-Wave communication systems.
The remainder of the article is organized as follows. The indicated design elements, antenna configuration and proposed antenna model strategy are presented in Section 2. Section 3 includes illustrations of surface current distribution and the effects of various variables. A study of the simulated and measured findings for the suggested antenna is presented in Section 4. A comparison with recently released state-of-the-art work is described in Section 5. Finally, the conclusion is given in Section 6.

Principle of Antenna Operation Mechanism
This section explains the proposed antenna mechanism operation, development stages and employed methodology. The antenna development phases are depicted in Figure 1a-d. The model employs an alternate-mixed approach and the overall antenna structure comprises an inverted triangular-shape, rectangle arms, elliptical cavity stubs, dielectric substrate, conducting material sheet (CMS), partial defected metal ground plane (PDMGP) and 50 Ω CPW feeding structure. These antenna components are etched on top of the low-cost Roger RT/Duroid 3010 TM printed circuit board (PCB) laminate material with constant dielectric of relative permittivity ε r = 11.2 and dielectric loss tangent δ = 0.0022. The front and lateral views of the radiator are illustrated in Figure 1e. The yellow and green regions represent the metallic radiating patch and the dielectric laminate. The design of semicircular inverted triangular-shaped (S C IT S ) slots and PDMGP with CPW feedline above the substrate forms the foundation of the envisaged radiator procedure. The CMS is placed on top of the substrate with a standard thickness of 0.035 mm. The antenna is positioned in an x-y position that is parallel to the z-axis. ture comprises an inverted triangular-shape, rectangle arms, elliptical cavity stubs, dielectric substrate, conducting material sheet (CMS), partial defected metal ground plane (PDMGP) and 50 Ω CPW feeding structure. These antenna components are etched on top of the low-cost Roger RT/Duroid 3010 TM printed circuit board (PCB) laminate material with constant dielectric of relative permittivity = 11.2 and dielectric loss tangent δ = 0.0022. The front and lateral views of the radiator are illustrated in Figure 1e. The yellow and green regions represent the metallic radiating patch and the dielectric laminate. The design of semicircular inverted triangular-shaped (SCITS) slots and PDMGP with CPW feedline above the substrate forms the foundation of the envisaged radiator procedure. The CMS is placed on top of the substrate with a standard thickness of 0.035 mm. The antenna is positioned in an x-y position that is parallel to the z-axis. Generally, it is challenging to attain perfect matching, particularly at a higher frequency band spectrum, for 5G mm-Wave wireless communication systems. In order to address this problem, further modification has been made to the initial designed antenna dimensions by loading the L-stub slot with PDMGP to obtain impedance BW, high gain and perfect matching, as illustrated in Figure 1b. Moreover, the symmetrically L-loaded slits are truncated by filleting the upper and lower edge corners (FT2) on both sides of the PDMGP. The gap of 0.475 mm between the CPW feeding network and PDMGP structures is carefully optimized to achieve 50 Ω matching. The simulated result of the return loss Generally, it is challenging to attain perfect matching, particularly at a higher frequency band spectrum, for 5G mm-Wave wireless communication systems. In order to address this problem, further modification has been made to the initial designed antenna dimensions by loading the L-stub slot with PDMGP to obtain impedance BW, high gain and perfect matching, as illustrated in Figure 1b. Moreover, the symmetrically L-loaded slits are truncated by filleting the upper and lower edge corners (F T2 ) on both sides of the PDMGP. The gap of 0.475 mm between the CPW feeding network and PDMGP structures is carefully optimized to achieve 50 Ω matching. The simulated result of the return loss |S 11 | parameter shows perfect matching (blue curve) as depicted in Figure 2. However, the main purpose of a design antenna is to achieve broad BW and high gain. To improve impedance matching, a further modified structure is used with an elliptically cut slit in a semicircular shape (S C ), as shown in Figure 1c. Fillet (F T1 ) operation is set at the inverted triangular-shaped (IT S ) corner edges and chamfering (C F1 ) cut into PDMGP on both sides. After performing a truncated S C -shaped elliptical stub, significant matching is obtained. To arrive at the desired objective, two more elliptical cavity radial stubs (C Sr1 and C Sr5 ) are interconnected with the antenna, as depicted in Figure 1d. To achieve broad BW optimal results, we have engraved another elliptical cavity slot stub, C Sr3 , cut from C Sr1 . Moreover, a symmetrical loaded L-shaped slot and an IT S with cavity radial stubs form the finalized compact radiating patch antenna prototype, as displayed in Figure 1e. The proposed antenna possesses overall small dimensions of 1.381λ 0 × 1.08λ 0 × 0.098λ 0 .
achieve appropriate impedance matching, it is essential to consider the PDMGP's width, length, radial cavity stubs, inverted triangle shape and substrate. Additionally, the antenna performance is significantly impacted by the inserting slots and their locations, tuning stubs and the gap (GAP1) between the PDMGP and CPW-feed; as a result, a broad impedance BW, enhanced high gain and flawless matching over a broad frequency range are achieved. The return loss |S11| parameter performance of the developed antenna prototypes is elucidated in Figure 2. It can be demonstrated that the proposed antenna structure obtained the perfect matching of fractional BW (red curve) from 23-42 GHz. Figure 3 depicts the simulated variation of the real and imaginary parts of the z-parameter. The plot shows that the input impedance of the port of the developed antenna was matched with the normalized z value of 50 Ω at the operable resonances.   Table 1 constructs the specification of the proposed antenna's optimal variables. To achieve appropriate impedance matching, it is essential to consider the PDMGP's width, length, radial cavity stubs, inverted triangle shape and substrate.
Additionally, the antenna performance is significantly impacted by the inserting slots and their locations, tuning stubs and the gap (G AP1 ) between the PDMGP and CPW-feed; as a result, a broad impedance BW, enhanced high gain and flawless matching over a broad frequency range are achieved. The return loss |S 11 | parameter performance of the developed antenna prototypes is elucidated in Figure 2. It can be demonstrated that the proposed antenna structure obtained the perfect matching of fractional BW (red curve) from 23-42 GHz. Figure 3 depicts the simulated variation of the real and imaginary parts of the z-parameter. The plot shows that the input impedance of the port of the developed antenna was matched with the normalized z value of 50 Ω at the operable resonances.

Simulation Results and Analysis
This section describes the analysis of the parametric study used to develop the proposed antenna design. The variables related to the specified parameters can be evaluated using meticulous iterative simulations. The essential purpose of this study is to obtain the best performance in terms of proper impedance matching and broad impedance BW. Further, the simulation results of the surface current distribution at multiple resonances of the proposed antenna are also discussed in this section.

Influence of CSr1 and CSr3
The composition of the semicircular radial cavity stub and elliptically loaded profiles is used to achieve antenna parameter accuracy. We embedded two cavity stubs from the initial design for the primary radiating purpose. The radiator of a developed antenna's impedance-matching performance is influenced by the size of the cavity radial stub 1 (CSr1) and cavity radial stub 3 (CSr3). The proper impedance matching and broader BW are attained at a main radiator patch size of 3.0 mm, as illustrated in Figure 4a. Moreover, at the value of CSr3 1.0 mm, ideal matching is obtained as shown in Figure 4b.

Simulation Results and Analysis
This section describes the analysis of the parametric study used to develop the proposed antenna design. The variables related to the specified parameters can be evaluated using meticulous iterative simulations. The essential purpose of this study is to obtain the best performance in terms of proper impedance matching and broad impedance BW. Further, the simulation results of the surface current distribution at multiple resonances of the proposed antenna are also discussed in this section.

Influence of C Sr1 and C Sr3
The composition of the semicircular radial cavity stub and elliptically loaded profiles is used to achieve antenna parameter accuracy. We embedded two cavity stubs from the initial design for the primary radiating purpose. The radiator of a developed antenna's impedance-matching performance is influenced by the size of the cavity radial stub 1 (C Sr1 ) and cavity radial stub 3 (C Sr3 ). The proper impedance matching and broader BW are attained at a main radiator patch size of 3.0 mm, as illustrated in Figure 4a. Moreover, at the value of C Sr3 1.0 mm, ideal matching is obtained as shown in Figure 4b.   Figure 5 portrays the semicircular cavity width (SCWC) and feedline width (WFL) that affect the overall performance of the proposed antenna. It is observed that the simulated result resonances obtained inclusive impedance BW performance. The SCWC stub radiator values range from 6.8 mm to 7.0 mm. The value of 7.0 mm yields the best impedancematching results, as illustrated in Figure 5a. The designed antenna feedline and two PDMGP grounds are the essential parts. An inverted triangle profile and a semicircular shaped radiator are coupled to ensure the proper transition. The feedline is used to excite the antenna radiator. In order to obtain the perfect impedance matching, selecting the ap-  Figure 5 portrays the semicircular cavity width (S C W C ) and feedline width (W FL ) that affect the overall performance of the proposed antenna. It is observed that the simulated result resonances obtained inclusive impedance BW performance. The S C W C stub radiator values range from 6.8 mm to 7.0 mm. The value of 7.0 mm yields the best impedance-matching results, as illustrated in Figure 5a. The designed antenna feedline and two PDMGP grounds are the essential parts. An inverted triangle profile and a semicircular shaped radiator are coupled to ensure the proper transition. The feedline is used to excite the antenna radiator. In order to obtain the perfect impedance matching, selecting the appropriate dimensions of the feedline is crucial. The feedline width (W FL ) fluctuation is between 1.05 mm to 1.45 mm and optimum results are obtained at the value of 1.25 mm, as depicted in Figure 5b.

Influence of WPDMGP and LPDMGP
The performance position of the CPW-e with defected ground surface is analyzed to improve the impedance characteristics. It is difficult to adjust the gap dimension between two partial defected ground planes with the center of the strip line. Figure 6a depicts the various opti-metric values used for the width of the partial defected metal ground planes (WPDMGP), ranging from 5.7 mm to 6.1 mm. It is observed that the proposed antenna attains proper matching at 5.9 mm, visible in a solid red line. Moreover, the effect of an L-shaped slot is truncated from the ground plane to obtain a broader BW. The variation in the length

Influence of W PDMGP and L PDMGP
The performance position of the CPW-e with defected ground surface is analyzed to improve the impedance characteristics. It is difficult to adjust the gap dimension between two partial defected ground planes with the center of the strip line. Figure 6a depicts the various opti-metric values used for the width of the partial defected metal ground planes (W PDMGP ), ranging from 5.7 mm to 6.1 mm. It is observed that the proposed antenna attains proper matching at 5.9 mm, visible in a solid red line. Moreover, the effect of an L-shaped slot is truncated from the ground plane to obtain a broader BW. The variation in the length of partial defected metal ground plane (L PDMGP ) values ranging from 4.1 mm to 4.9 mm is fixed. It is noted that the proposed antenna reaches proper matching at 4.5 mm, as portrayed in Figure 6b.

Surface Current Distribution (JSURF)
The current intensity across the radiator's surface is examined and evaluated to validate the effectiveness. Figures 7a-d show the current distributed density over the proposed antenna lattice at various resonances. This is evident at 26.25 GHz; resonance shows that the surface current density is much stronger around the inner and outer edges of the semicircular inverted triangular-shaped patch, as shown in Figure 7a. An L-stub is loaded

Surface Current Distribution (J SURF )
The current intensity across the radiator's surface is examined and evaluated to validate the effectiveness. Figure 7a-d show the current distributed density over the proposed antenna lattice at various resonances. This is evident at 26.25 GHz; resonance shows that the surface current density is much stronger around the inner and outer edges of the semicircular inverted triangular-shaped patch, as shown in Figure 7a. An L-stub is loaded at PDMGP and transmission line with an inverted triangle at the higher current distribution at 29.75 GHz resonance, as illustrated in Figure 7b. Therefore, the resonant frequency is decreased and additional resonances are introduced with the second resonant of the antenna. This leads to the realizing of broadband resonance response features. It also indicates that the strong current is centered along the elliptical radiator's structure of the 50 Ω CPW feedline. However, a slight fluctuation in current flow at higher resonances, such as 35.65 GHz and 38 GHz, can be seen on the radiator stubs and the slotted edge of the partially defected ground planes, as portrayed in Figure 7c,d. at PDMGP and transmission line with an inverted triangle at the higher current distribution at 29.75 GHz resonance, as illustrated in Figure 7b. Therefore, the resonant frequency is decreased and additional resonances are introduced with the second resonant of the antenna. This leads to the realizing of broadband resonance response features. It also indicates that the strong current is centered along the elliptical radiator's structure of the 50 Ω CPW feedline. However, a slight fluctuation in current flow at higher resonances, such as 35.65 GHz and 38 GHz, can be seen on the radiator stubs and the slotted edge of the partially defected ground planes, as portrayed in Figure 7c-d.

Experimentally Validated Results
This section concentrates on the experimental outcomes of return loss |S11| (dB), peak realized gain (dBi), radiation efficiency (%) and far-field radiation patterns along the E-H plane. Further, the results are also investigated and analyzed in this section.

Return Loss |S11| Parameter
This segment presents the return loss |S11| performance of the manufactured and designed antenna. Figures 8a,b display a manufactured antenna sample. It can be seen that the middle pin of the SMA 50 Ω connector is soldered at the center of the CPW feedline and two more conductor pins are engraved with PDMGP. The |S11| performance for

Experimentally Validated Results
This section concentrates on the experimental outcomes of return loss |S 11 | (dB), peak realized gain (dBi), radiation efficiency (%) and far-field radiation patterns along the E-H plane. Further, the results are also investigated and analyzed in this section.

Return Loss |S 11 | Parameter
This segment presents the return loss |S 11 | performance of the manufactured and designed antenna. Figure 8a,b display a manufactured antenna sample. It can be seen that the middle pin of the SMA 50 Ω connector is soldered at the center of the CPW feedline and two more conductor pins are engraved with PDMGP. The |S 11 | performance for all of the experiment's frequency sweeps is shown in Figure 8. The vector network analyzer (VNA) is precisely calibrated before assessing the fabricated antenna return loss |S 11 |. The microwave cable is connected to the port of the calibrated VNA N5244A Agilent technologies. The simulation and measurement results of the proposed design are depicted in Figure 9. Good agreement between the designed and fabricated models can be seen from Figure 9. However, there is a modest change in the resonances in the measurement's outcome. picted in Figure 9. Good agreement between the designed and fabricated models can be seen from Figure 9. However, there is a modest change in the resonances in the measurement's outcome.
The slight changes in the results may be due to the fabrication tolerances in the manufacturing of the substrate material, thickness, loss tangent or relative permittivity values, and improper soldering. It is clearly seen that the antenna's simulation design has a broader impedance BW range from 23-42 GHz, resulting in 58.46%, which can be resonated at multiple frequencies. Moreover, the other two resonances are centered at 29.75 GHz and 35.65 GHz as depicted in Figure 9. As can be seen in the measured results (blue curve), at 35.65 GHz resonance there has been a slight shift in the resonance in the simulated result. Small variations have been obtained due to the glossy substrate material and the defective soldering of the SMA connector. Besides, higher resonance is observed at 38 GHz. The 28 GHz/38 GHz frequency band for mm-Wave 5G wireless communication systems may also be covered.  picted in Figure 9. Good agreement between the designed and fabricated models can be seen from Figure 9. However, there is a modest change in the resonances in the measurement's outcome. The slight changes in the results may be due to the fabrication tolerances in the manufacturing of the substrate material, thickness, loss tangent or relative permittivity values, and improper soldering. It is clearly seen that the antenna's simulation design has a broader impedance BW range from 23-42 GHz, resulting in 58.46%, which can be resonated at multiple frequencies. Moreover, the other two resonances are centered at 29.75 GHz and 35.65 GHz as depicted in Figure 9. As can be seen in the measured results (blue curve), at 35.65 GHz resonance there has been a slight shift in the resonance in the simulated result. Small variations have been obtained due to the glossy substrate material and the defective soldering of the SMA connector. Besides, higher resonance is observed at 38 GHz. The 28 GHz/38 GHz frequency band for mm-Wave 5G wireless communication systems may also be covered.  The slight changes in the results may be due to the fabrication tolerances in the manufacturing of the substrate material, thickness, loss tangent or relative permittivity values, and improper soldering. It is clearly seen that the antenna's simulation design has a broader impedance BW range from 23-42 GHz, resulting in 58.46%, which can be resonated at multiple frequencies. Moreover, the other two resonances are centered at 29.75 GHz and 35.65 GHz as depicted in Figure 9. As can be seen in the measured results (blue curve), at 35.65 GHz resonance there has been a slight shift in the resonance in the simulated result. Small variations have been obtained due to the glossy substrate material and the defective soldering of the SMA connector. Besides, higher resonance is observed at 38 GHz. The 28 GHz/38 GHz frequency band for mm-Wave 5G wireless communication systems may also be covered.

Peak Realized Gain and Radiation Efficiency
The simulation and measurement results of peak realized gain and radiation efficiency against the designated frequency span are presented in Figure 10a

Peak Realized Gain and Radiation Efficiency
The simulation and measurement results of peak realized gain and radiation efficiency against the designated frequency span are presented in Figure 10  Besides, the ratio of radiated to accepted power is known as the radiation efficiency, which is a crucial antenna characteristic. The simulated and measured radiation efficiency plot is shown in Figure 10b. The efficiency of the manufactured prototype is computed using an easy, reliable and rapid method based on the directivity/gain information. The measured radiation efficiency is used to obtain the following equation: where is denoted by the fraction of , and which represents the designed antenna's simulated and measured gain and directivity. The operable BW obtains the better simulated efficiency of 89% and tested 13.2% variance over the entire frequency span.

Radiation Pattern Performance
The proposed antenna radiation patterns in the standard planes are measured inside the anechoic chamber under far-field conditions. In Figures 11a,b, the arrangement of the antenna under test (AUT) is depicted. The elevation (E-plane) and Azimuth (H-plane) of the manufactured antenna prototype are measured inside the anechoic chamber room. Moreover, the radio-absorbing material has been used to cover the indoor measurement Besides, the ratio of radiated to accepted power is known as the radiation efficiency, which is a crucial antenna characteristic. The simulated and measured radiation efficiency plot is shown in Figure 10b. The efficiency of the manufactured prototype is computed using an easy, reliable and rapid method based on the directivity/gain information. The measured radiation efficiency is used to obtain the following equation: where η msd is denoted by the fraction of G msd , and D smd which represents the designed antenna's simulated and measured gain and directivity. The operable BW obtains the better simulated efficiency of 89% and tested 13.2% variance over the entire frequency span.

Radiation Pattern Performance
The proposed antenna radiation patterns in the standard planes are measured inside the anechoic chamber under far-field conditions. In Figure 11a,b, the arrangement of the antenna under test (AUT) is depicted. The elevation (E-plane) and Azimuth (H-plane) of the manufactured antenna prototype are measured inside the anechoic chamber room. Moreover, the radio-absorbing material has been used to cover the indoor measurement facility walls. AUT was placed at the distance of the standard horn antenna. The positioner controller has been used to operate the proposed model table, which is wired via Ethernet to the computer. The AUT (receiver) and the typical standard horn antenna (transmitter) were set in a line of sight (L O S) at a specific distance. In addition, the AUT port is connected with a microwave cable (purple color) to the VNA as can be seen in Figure 11a. The installation of a computer allows for monitoring of measurement results, executing commands and storing measured data. The overall measurement setup is graphically represented in Figure 12. facility walls. AUT was placed at the distance of the standard horn antenna. The positioner controller has been used to operate the proposed model table, which is wired via Ethernet to the computer. The AUT (receiver) and the typical standard horn antenna (transmitter) were set in a line of sight (LOS) at a specific distance. In addition, the AUT port is connected with a microwave cable (purple color) to the VNA as can be seen in Figure 11a. The installation of a computer allows for monitoring of measurement results, executing commands and storing measured data. The overall measurement setup is graphically represented in Figure 12.    facility walls. AUT was placed at the distance of the standard horn antenna. The positioner controller has been used to operate the proposed model table, which is wired via Ethernet to the computer. The AUT (receiver) and the typical standard horn antenna (transmitter) were set in a line of sight (LOS) at a specific distance. In addition, the AUT port is connected with a microwave cable (purple color) to the VNA as can be seen in Figure 11a. The installation of a computer allows for monitoring of measurement results, executing commands and storing measured data. The overall measurement setup is graphically represented in Figure 12.      Figure 13a. It can be seen that the characteristics as essentially a fixed stable radiation pattern which radiates equally over 360 • . Moreover, the side lobes are visible at an angle of 300 • and 340 • in the measured results (blue curve) of the radiation pattern at 29.75 GHz as illustrated in Figure 13b.
planes. The displayed results can be observed consistently. The characteristics of the antenna radiation pattern are towards the 0° main lobe directions. The lower frequency resonance at 26.25 GHz of the radiation pattern is depicted in Figure 13a. It can be seen that the characteristics as essentially a fixed stable radiation pattern which radiates equally over 360°. Moreover, the side lobes are visible at an angle of 300° and 340° in the measured results (blue curve) of the radiation pattern at 29.75 GHz as illustrated in Figure 13b. Furthermore, the antenna radiates 0° in the main lobe directions at 35.65 GHz, as portrayed in Figure 13c. However, there is a slight shift in the measured H-planes' results as compared to the simulated results. Moreover, a perfect main lobe beam is seen at the 38 GHz resonance frequency in Figure 13d. The slotted antenna is primarily responsible for this observed variation in the radiation pattern at higher resonances. Because higherorder modes produce highly stable radiation characteristics in both standardized planes, the resultant far field fixed beam at higher frequencies' radiation characteristics are visible. The aforementioned radiation patterns exhibit stability and act at specific resonances like fixed omnidirectional-shaped patterns. In addition, the patterns show a minor distortion at center frequencies. Due to chamber losses and glossy material, some asymmetry in the measured patterns is seen.   Figure 13c. However, there is a slight shift in the measured H-planes' results as compared to the simulated results. Moreover, a perfect main lobe beam is seen at the 38 GHz resonance frequency in Figure 13d. The slotted antenna is primarily responsible for this observed variation in the radiation pattern at higher resonances. Because higher-order modes produce highly stable radiation characteristics in both standardized planes, the resultant far field fixed beam at higher frequencies' radiation characteristics are visible. The aforementioned radiation patterns exhibit stability and act at specific resonances like fixed omnidirectional-shaped patterns. In addition, the patterns show a minor distortion at center frequencies. Due to chamber losses and glossy material, some asymmetry in the measured patterns is seen.

Comparison Analysis
The proposed design model of the antenna exhibits excellent performance results of broad impedance BW and peak realized gain with a low profile. A comparative analysis of the antenna key features with state-of-the-art work is shown in Table 2. The proposed antenna has a good BW performance of 58.46%, particularly for the 5G mm-Wave spectrum as compared with refs. [30,37,38,43,45]. The reported antennas achieved a good BW with a complicated assembly and complex geometrical structure. Another work-based CPW-fed broadband slotted antenna with different shapes has been investigated in [44]. The reported antenna structure obtained fair impedance BW at multiple frequencies with computational complexity. The results of the comparative analysis state that, compared to the proposed antenna, most of the reported works on 5G mm-Wave broadband antennas cover a limited frequency spectrum. It is concluded that the proposed model achieved a broad impedance BW of 58.46% as compared to the most examples in the reported work.

Conclusions
A new semicircular inverted triangular shaped antenna based on a mixed-alternate approach has been presented for the 5G mm-Wave wireless communication system. The new design approach is based on the cavity, slots and loaded stubs. The proposed model exhibited broad impedance BW results at 58.46%, radiation efficiency of 89% and a highgain of 6.75 dBi. The model is formed of an inverted-triangular arm radiator, metal ground plane and standard 50 Ω CPW feedline. The antenna elements were printed on low-cost Roger laminate material. The proposed antenna has a small dimension of 1.381λ 0 × 1.08λ 0 × 0.098λ 0 . The influence of multiple variables has been analyzed and discussed. The antenna model exhibited an excellent return loss performance, peak realized gain and stable far-field E-H radiation patterns. The intended antenna achieved in-band resonances with a broad impedance BW of 23-42 GHz. The suggested antenna demonstrated a good current distribution across the operable frequency range, a consistent omnidirectional radiation pattern and a reasonable peak realized gain performance of 6.75 dBi at lower frequency resonance of 26.25 GHz. The simulation and measured results are in close agreement and hence make the proposed antenna a competitive choice for 5G mm-Wave wireless communication applications. Moreover, the presented work may be further extended to design a MIMO antenna array topology.

Data Availability Statement:
The data used to support the findings of this study are included within the article.