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Electronics
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Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems
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Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems

A special issue of Electronics (ISSN 2079-9292). This special issue belongs to the section "Microwave and Wireless Communications".

Deadline for manuscript submissions: closed (15 August 2023) | Viewed by 24792

Special Issue Editors

Dr. Mohammad Maktoomi

E-Mail Website
Guest Editor
Assistant Professor, Electrical & Computer Engineering, Virginia Military Institute (VMI), Lexington, VA 24450, USA
Interests: MIC and MMIC radio-frequency/microwave circuits and systems for wireless communications and Internet-of-Things applications
Dr. Tutku Karacolak

E-Mail Website
Guest Editor
School of Engineering and Computer Science, Washington State University Vancouver, Vancouver, WA 98686, USA
Interests: antenna analysis and design; bioelectromagnetics; full-duplex systems for compact low-power devices
Special Issues, Collections and Topics in MDPI journals
Dr. Mohamed Helaoui

E-Mail
Guest Editor
Department of Electrical and Software Engineering, University of Calgary, Calgary, AB, Canada
Interests: MIC and MMIC circuits and systems; RF transceivers
Special Issues, Collections and Topics in MDPI journals
Dr. Syed Azeemuddin

E-Mail Website
Guest Editor
Electrical and Computer Engineering, University of Mississippi, University, MS 38677, USA
Interests: RFIC; integrated photonics; RF and optics sensors

Special Issue Information

Dear Colleagues,

RF/microwave circuits and systems play a crucial role in all modern wireless communication and Internet of Things (IoT) applications. It is no exaggeration to claim that not even a single aspect of our lives is untouched by RF/microwave technologies; they are ubiquitous—from the wireless doorbell to keyless entry to our cars, from cooking to industrial heating, from cell phone to computer systems, from medicine to space technologies, they are everywhere. The vast and rapid technological development at many levels (e.g., in semiconductor device technologies, simulation models, component miniaturization, and system architectures to name a few) has enabled this enormous penetration of RF/microwave circuits and systems in our modern lives.

This Special Issue of the MDPI journal Electronics entitled "Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems" solicits original contributions with a special focus on recent developments in the analysis, design, implementation, and measurement of MIC, MMIC, and CMOS RF and microwave circuits and systems. Topics of interest include a vast array of passive and active circuits and systems (including, but not limited to): impedance-matching networks, filters, device modeling, amplifiers (PAs and LNAs), RF transceivers, digital predistortion (DPD), power dividers/combiners, couplers, antennas, diplexers/multiplexers, wireless power transfer, energy harvesting, etc. Authors are welcome to submit regular research articles as well as nicely written review papers.

Dr. Mohammad Maktoomi
Dr. Tutku Karacolak
Dr. Mohamed Helaoui
Dr. Syed Azeemuddin
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Electronics is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • power divider/coupler
  • amplifier
  • transceivers
  • DPD
  • filter
  • antenna
  • wireless power transfer
  • energy harvesting

Published Papers (16 papers)

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Research

15 pages, 1483 KiB  
Article
Miniaturized Dual-Band SIW-Based Bandpass Filters Using Open-Loop Ring Resonators
by Nrusingha Charan Pradhan, Slawomir Koziel, Rusan Kumar Barik, Anna Pietrenko-Dabrowska and Sholampettai Subramanian Karthikeyan
Electronics 2023, 12(18), 3974; https://doi.org/10.3390/electronics12183974 - 21 Sep 2023
Cited by 5 | Viewed by 1164
Abstract
This article presents two novel architectures of dual-band substrate-integrated waveguide (SIW) bandpass filters (BPFs). Initially, two identical open-loop ring resonators (OLRRs) were coupled face-to-face on the top of the SIW cavity to realize a dual-band single-pole BPF. To obtain two-pole dual-band characteristics, two [...] Read more.
This article presents two novel architectures of dual-band substrate-integrated waveguide (SIW) bandpass filters (BPFs). Initially, two identical open-loop ring resonators (OLRRs) were coupled face-to-face on the top of the SIW cavity to realize a dual-band single-pole BPF. To obtain two-pole dual-band characteristics, two OLRRs resonant units were assembled horizontally within the top metal layer of the SIW, which is a technique used for the first time in the literature. For demonstration purposes, two types of SIW filters loaded with OLRRs were designed and fabricated. The proposed filters feature an extremely compact size, a low insertion loss, and good selectivity. The single- and two-pole filters have an overall size of 0.012λg2 and 0.041λg2, respectively. The simulated and measured circuit responses are in good agreement. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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9 pages, 3789 KiB  
Communication
Design Technique of K-Band CMOS Phase Shifter with L-C-L T-Type Low Pass Structure
by Seongjin Jang, Choul-Young Kim and Changkun Park
Electronics 2023, 12(17), 3678; https://doi.org/10.3390/electronics12173678 - 31 Aug 2023
Cited by 2 | Viewed by 655
Abstract
In this study, we designed a 5-bit K-band CMOS switch type phase shifter. In order to minimize phase and gain errors, a design technique for bits constituting the phase shifter was proposed. The proposed design technique has been achieved by adjusting the resonant [...] Read more.
In this study, we designed a 5-bit K-band CMOS switch type phase shifter. In order to minimize phase and gain errors, a design technique for bits constituting the phase shifter was proposed. The proposed design technique has been achieved by adjusting the resonant frequencies of inductance and capacitance in the L-C-L T-type low pass filter structure. Through this, a method of optimizing the phase shifter with the T-type low pass filter structure was presented. The K-band 5-bit phase shifter was designed with a 65 nm CMOS process to verify the feasibility of the proposed design technique. The core size was 0.78 × 0.21 mm2. At the frequency ranges of 22.0 to 23.0 GHz, the insertion loss and RMS phase and gain errors were measured to be 7.44 ± 2.0 dB, 2.6°, and 1.2 dB, respectively. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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14 pages, 4312 KiB  
Article
Low-Cost W-Band Dual-Mode SIW Bandpass Filters Using Commercially Available Printed-Circuit-Board Technology
by Xiaolong Huang and Zheng Liu
Electronics 2023, 12(17), 3624; https://doi.org/10.3390/electronics12173624 - 27 Aug 2023
Cited by 4 | Viewed by 1077
Abstract
W-band filters play a crucial role in modern millimeter-wave communication and radar systems, finding applications in 5G/6G networks, automotive radar, and passive imaging. With the growing demand for higher data rates and efficient wireless communication, W-band filter development has gained significant attention in [...] Read more.
W-band filters play a crucial role in modern millimeter-wave communication and radar systems, finding applications in 5G/6G networks, automotive radar, and passive imaging. With the growing demand for higher data rates and efficient wireless communication, W-band filter development has gained significant attention in recent years. Various design techniques and fabrication technologies have been explored for improved performance and integration possibilities. This paper presents a planar substrate-integrated waveguide (SIW) dual-mode cavity filter as a solution to the challenges faced by previous designs in terms of integration, size, and cost. The dual-mode cavity coupling principle and design parameters are analyzed to optimize the filter’s performance. A W-band 4th-order dual-mode filter prototype is designed and fabricated on a 0.127-mm-thick RO5880 substrate, and a finline waveguide-to-microstrip transition structure is employed for compatibility with the test instrument. Simulation and experimental results demonstrate that the proposed filter exhibits low insertion loss, good in-band standing wave performance, and improved out-of-band suppression. Moreover, a visible high-frequency out-of-band transmission zero is implemented to enhance the steep roll-off characteristics in the high-frequency out-of-band region. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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9 pages, 3753 KiB  
Communication
W-Band GaN HEMT Switch Using the State-Dependent Concurrent Matching Method
by Hyemin Im, Jaeyong Lee and Changkun Park
Electronics 2023, 12(10), 2236; https://doi.org/10.3390/electronics12102236 - 15 May 2023
Cited by 1 | Viewed by 967
Abstract
In this study, a W-band GaN single-pole single-throw (SPST) switch was designed. To realize the pass and isolation modes of the SPST switch, we proposed the design technique of a unit branch consisting of one transistor and one transmission. The characteristic impedance and [...] Read more.
In this study, a W-band GaN single-pole single-throw (SPST) switch was designed. To realize the pass and isolation modes of the SPST switch, we proposed the design technique of a unit branch consisting of one transistor and one transmission. The characteristic impedance and length of the transmission line were determined by the impedance and the angle at which the straight line connecting the impedances of the on and off states of the transistor meets the real axis of the Smith chart. Using the design technique, the matching networks for the pass and isolation modes of the switch are concurrently completed. In order to improve the insertion loss and isolation characteristics of the switch, the size of the transistor and the number of unit branches were investigated. To verify the feasibility of the proposed design technique, we designed the W-band SPST switch using a 100 nm GaN HEMT process. The measured insertion loss and isolation were below 2.9 dB and above 23.5 dB, respectively, in the frequency range from 91 GHz to 101 GHz. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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11 pages, 5131 KiB  
Article
Design of 6 GHz Variable-Gain Low-Noise Amplifier Using Adaptive Bias Circuit for Radar Receiver Front End
by Hyungseok Nam, Dang-An Nguyen, Yanghyun Kim and Chulhun Seo
Electronics 2023, 12(9), 2036; https://doi.org/10.3390/electronics12092036 - 27 Apr 2023
Viewed by 1300
Abstract
This paper presents a variable-gain low-noise amplifier (VGLNA) based on an adaptive bias (ADB) circuit for the radar receiver front end. The ADB circuit processes the signal separated by a coupler at the LNA output port. First, the ADB circuit rectifies the coupled [...] Read more.
This paper presents a variable-gain low-noise amplifier (VGLNA) based on an adaptive bias (ADB) circuit for the radar receiver front end. The ADB circuit processes the signal separated by a coupler at the LNA output port. First, the ADB circuit rectifies the coupled signal into positive DC voltage through a rectifier, which is then inverted to control a junction-gate field-effect transistor (JFET). The voltage-controlled current of JFET flows through a voltage-divider network and finally produces the DC biasing voltage for the BJT base termination, which decreases with the increase in the input RF power. The proposed VGLNA operates automatically in high gain at low input power and low gain at high input power, providing a wider dynamic range as compared to the constant-bias counterpart. For validation, a prototype is fabricated and measured at 6 GHz. As observed, the base biasing voltage generated by the ADB circuit is changed from 858 mV to 798 mV as the input power increases from −50 dBm to 0 dBm. As a result, the dynamic range represented by the input P1dB point (IP1dB) has an increase of 6.5 dB, while LNA still maintains a high gain of 15.15 dB at low input power. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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16 pages, 9700 KiB  
Article
Additive Manufacturing of a Miniaturized X-Band Single-Ridge Waveguide Magic-T for Monopulse Radar Applications
by Riccardo Rossi, Roberto Vincenti Gatti, Flaviana Calignano, Luca Iuliano and Simona Chiarandini
Electronics 2023, 12(5), 1124; https://doi.org/10.3390/electronics12051124 - 25 Feb 2023
Viewed by 1560
Abstract
A low-profile single-ridge waveguide magic-T is proposed as a combination of two T-junctions at an X band. A slot coupling technique is used to reduce the component dimensions in the E-plane, thus leading to a low profile. The device can assume two configurations [...] Read more.
A low-profile single-ridge waveguide magic-T is proposed as a combination of two T-junctions at an X band. A slot coupling technique is used to reduce the component dimensions in the E-plane, thus leading to a low profile. The device can assume two configurations by arranging the sum and difference ports in the same or opposite direction, an attractive feature in the design of beamforming networks with complex routing. A magic-T prototype is fabricated using laser powder bed fusion additive manufacturing techniques. Good agreement between simulations and measurements is found. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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13 pages, 3254 KiB  
Article
New Miniature Narrow Band Microstrip Diplexer for Recent Wireless Communications
by Kadhum Al-Majdi and Yaqeen Sabah Mezaal
Electronics 2023, 12(3), 716; https://doi.org/10.3390/electronics12030716 - 1 Feb 2023
Cited by 5 | Viewed by 1697
Abstract
Using Kappa substrate material, a compact microstrip diplexer is developed in this research with two separate channels based on the coupled junction and two bandpass filters functioning in independent frequency bands. Each filter comprises an input/output feed line and a number of resonators [...] Read more.
Using Kappa substrate material, a compact microstrip diplexer is developed in this research with two separate channels based on the coupled junction and two bandpass filters functioning in independent frequency bands. Each filter comprises an input/output feed line and a number of resonators with different impedances. The diplexer’s frequency response was modeled and optimized using the Sonnet EM solver. At 2.84 and 4.08 GHz for TX/RX channels, the insertion loss is better than 1 dB for both channels, while the return loss values are 21.2 and 17 dB for transmit and receive filters, respectively. The microstrip diplexer has miniature dimensions of 24 mm × 18 mm with highly narrow bands and band isolation of more than 35 dB. The simulated scattering parameters are in agreement with the measured ones. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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9 pages, 2612 KiB  
Communication
A Novel Self-Adaptive Rectifier with High Efficiency and Wide Input Power Range
by Shimiao Lai, Zihao Zhang, Zhijun Liu, Ge Wang, Yongjie Zhou, Huacheng Zhu and Yang Yang
Electronics 2023, 12(3), 712; https://doi.org/10.3390/electronics12030712 - 31 Jan 2023
Viewed by 1356
Abstract
A novel 2.45 GHz self-adaptive rectifier with high efficiency and a wide input power range is proposed in this paper. It consists of a high-power sub-rectifier branch, a low-power sub-rectifier branch, an impedance transform and isolation network (ITIN), and a feedback network. Impedance [...] Read more.
A novel 2.45 GHz self-adaptive rectifier with high efficiency and a wide input power range is proposed in this paper. It consists of a high-power sub-rectifier branch, a low-power sub-rectifier branch, an impedance transform and isolation network (ITIN), and a feedback network. Impedance matching is realized by ITIN for both branches. The proposed design is able to switch between these two branches by the feedback network according to its output voltage level. The rectifier has been simulated, fabricated, and tested. The measured power conversion efficiency (PCE) exceeds 50% over the input power range from 5 to 29 dBm, with a total dynamic range of 24 dB. The input range when PCE exceeds 60% is from 10 dBm to 28 dBm. The maximum efficiency is 75.2% at 26 dBm input power. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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16 pages, 7181 KiB  
Article
An H-Plane Groove Gap Waveguide Magic-T for X-Band Applications
by Riccardo Rossi and Roberto Vincenti Gatti
Electronics 2022, 11(24), 4075; https://doi.org/10.3390/electronics11244075 - 8 Dec 2022
Cited by 1 | Viewed by 1453
Abstract
An X-band H-plane groove gap waveguide magic-T is presented as a combination of an H-plane and an E-plane T-junction. Two architectures can be derived by orientating the sum and difference ports to the same or opposite directions, respectively. Slot coupling allows the reduction [...] Read more.
An X-band H-plane groove gap waveguide magic-T is presented as a combination of an H-plane and an E-plane T-junction. Two architectures can be derived by orientating the sum and difference ports to the same or opposite directions, respectively. Slot coupling allows the reduction of the device dimensions along the E-plane, and such a low profile can be attractive in all groove gap waveguide applications where compactness is required. A proof-of-concept prototype is fabricated with standard low-cost CNC milling machine manufacturing techniques. Good agreement between simulations and measurements is observed. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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16 pages, 9076 KiB  
Article
A C/X/Ku/K-Band Precision Compact 6-Bit Digital Attenuator with Logic Control Circuits
by Jialong Zeng, Jiaxuan Li, Yang Yuan, Cheng Tan and Zhongjun Yu
Electronics 2022, 11(21), 3620; https://doi.org/10.3390/electronics11213620 - 6 Nov 2022
Cited by 2 | Viewed by 1632
Abstract
This paper proposes a C/X/Ku/K band 6-bit digital step attenuator (DSA) which employs a variety of improved attenuation cells to achieve a wide bandwidth, stable amplitude variation, stable phase variation, and small area. In this paper, the improved T-type, π-type, and switched-path type [...] Read more.
This paper proposes a C/X/Ku/K band 6-bit digital step attenuator (DSA) which employs a variety of improved attenuation cells to achieve a wide bandwidth, stable amplitude variation, stable phase variation, and small area. In this paper, the improved T-type, π-type, and switched-path type topologies are analyzed theoretically and applied to different attenuation values to achieve the optimal attenuator performance. In addition, in order to reduce the complexity and to improve the stability of the overall radar system, the logic control circuit is integrated in the DSA chip in this paper. Finally, the proposed attenuator is implemented in 0.15μm GaAs technology, which has a maximum attenuation range of 31.5 dB with 0.5 dB steps. The proposed DSA exhibits a root-mean-square (RMS) attenuation error of less than 0.15 dB and an RMS phase error of less than 3°, at 4–24 GHz. The insertion loss (IL) and the area of the DSA are 4.3–4.5 dB and 1.5 mm × 0.4 mm, respectively. Benefiting from the improvements of the attenuation cells and the characteristic of GaAs technology with strong resistance to radiation and power processing capability, the proposed DSA is suitable for spaceborne radar systems. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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17 pages, 9491 KiB  
Article
Tightly Coupled Ultra-Wideband Phased-Array Implemented by Three-Dimensional Inkjet Printing Technique
by Lei Han, Gang Wang, Lin Zhang, Weixu Jiang, Pengbing Zhao, Wei Tang, Tao Dang and Hongxing Zheng
Electronics 2022, 11(20), 3320; https://doi.org/10.3390/electronics11203320 - 14 Oct 2022
Cited by 3 | Viewed by 1442
Abstract
In order to enhance the gains from antennas suitable for airplane-mounted platforms, a tightly coupled antenna array is investigated in this paper. Specifically, a three-dimensional (3-D) inkjet printing technique is used to implement the conformal characteristics needed for the array. Both the radiators [...] Read more.
In order to enhance the gains from antennas suitable for airplane-mounted platforms, a tightly coupled antenna array is investigated in this paper. Specifically, a three-dimensional (3-D) inkjet printing technique is used to implement the conformal characteristics needed for the array. Both the radiators and substrate of the antenna array have been fabricated by combining the fused deposition modeling and microdroplet injection molding technologies, based on an existing 3-D printer. Here, through a unique combination of 3-D and 2-D inkjet printing of dielectric material and metallic ink, respectively, we demonstrate a monolithically integrated design for a nonplanar antenna for the first time. The antenna measurements herein show the complete characterization of this new process in terms of minimum feature size and achievable conductivities. This antenna configuration offers a high-gain performance with a low-cost and rapid fabrication technique by using 3-D printing techniques. To check our design, the voltage standing wave ratio and radiation patterns were tested after adding the newly designed feed structure. The results show that the design process is very efficient. Both the antenna element and the array demonstrate positive properties and are in very good agreement with the specially mounted platform. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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11 pages, 3343 KiB  
Article
Experimental Characterization of Millimeter-Wave Substrate-Integrated Waveguide Interconnect with Slot Transition in Flexible Printed Circuit Boards
by Myunghoi Kim, Bumhee Bae and Jeongnam Cheon
Electronics 2022, 11(19), 2995; https://doi.org/10.3390/electronics11192995 - 21 Sep 2022
Cited by 2 | Viewed by 1517
Abstract
For high-speed communication services such as 5G technology, the use of millimeter-wave (mmWave) components substantially increases in mobile applications. The interconnect based on a substrate-integrated waveguide (SIW) is an efficient solution for connecting these devices. However, the SIW characteristics in the mmWave frequency [...] Read more.
For high-speed communication services such as 5G technology, the use of millimeter-wave (mmWave) components substantially increases in mobile applications. The interconnect based on a substrate-integrated waveguide (SIW) is an efficient solution for connecting these devices. However, the SIW characteristics in the mmWave frequency range are not sufficiently presented from the practical viewpoint. In this paper, the experimental characterization of mmWave SIWs in flexible printed circuit boards (FPCBs) and their simulation results are presented. A practical method using balanced/single slot transition is proposed for microstrip-to-SIW transition. Using a full-wave simulation and genetic algorithm, the proposed slot technique is optimized. It is experimentally demonstrated that the cutoff frequency affects the operating band of the SIW differently. The per-unit-length losses of the full-mode and half-mode SIWs are obtained as 0.0375 dB/mm and 0.0609 dB/mm, respectively. Using the measurements, the SIW type effect on the transmission loss is quantitatively analyzed, and the loss is increased up to 62.4% at 39 GHz. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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18 pages, 3441 KiB  
Article
Experimental Realization of 16-Pixel Terahertz Receiver Front-End Based on Bulk Silicon MEMS Power Divider and AlGaN/GaN HEMT Linear Detector Array
by Kaiqiang Zhu, Qingfeng Ding, Tong Mao, Xiuming Tang, Yu Xiao, Hua Qin and Houjun Sun
Electronics 2022, 11(15), 2305; https://doi.org/10.3390/electronics11152305 - 23 Jul 2022
Cited by 2 | Viewed by 1743
Abstract
A 16-pixel terahertz (THz) receiver front-end working at room temperature was designed, built, and measured in this paper. The designed receiver front-end is based on the antenna-coupled AlGaN/GaN high-electron-mobility transistor (HEMT) THz linear detector array (TeraLDA) and a 16-way THz power divider. The [...] Read more.
A 16-pixel terahertz (THz) receiver front-end working at room temperature was designed, built, and measured in this paper. The designed receiver front-end is based on the antenna-coupled AlGaN/GaN high-electron-mobility transistor (HEMT) THz linear detector array (TeraLDA) and a 16-way THz power divider. The local oscillator (LO) signal is divided by the power divider into 16 ways and transmits to the TeraLDA. Each detector contains a planar unified antenna printed on a 150 μm-thick sapphire substrate and a transistor fabricated on AlGaN/GaN heterostructure. There are 16 silicon hemispheric lenses located on the TeraLDA to increase the responsivity of the TeraLDA. The focus of each lens is aligned in the center of the TeraLDA pixels. Depending on different read out circuits, the receiver front-end could work in homodyne and heterodyne modes. The 16-way power divider is a four-stage power divider that consists of fifteen same 2-way dividers, and was fabricated by bulk silicon microelectromechanical systems (MEMS) technology to achieve low insertion loss (IL). This designed receiver front-end could be a key component of a THz coherent focal plane imaging radar system, that may play a crucial role in nondestructive 3D imaging application. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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7 pages, 3488 KiB  
Article
A Wideband 6-Bit Digital Attenuator in a GaAs pHEMT MMIC
by Dongning Hao, Wei Zhang, Xiubo Liu and Yanyan Liu
Electronics 2022, 11(14), 2166; https://doi.org/10.3390/electronics11142166 - 11 Jul 2022
Cited by 8 | Viewed by 1699
Abstract
A low insertion loss, wideband 6-bit digital step attenuator is implemented in the 0.25-μm GaAs pHEMT process. Modified π- or T-type attenuator structures are adopted to expand the operation frequency bandwidth and reduce the insertion phase violation. Furthermore, the through-wafer via (TWV) is [...] Read more.
A low insertion loss, wideband 6-bit digital step attenuator is implemented in the 0.25-μm GaAs pHEMT process. Modified π- or T-type attenuator structures are adopted to expand the operation frequency bandwidth and reduce the insertion phase violation. Furthermore, the through-wafer via (TWV) is analyzed to reduce the influence of the parasitic effect on the high-frequency performance of the attenuator. The depletion mode single-gate switch transistors are used to control the on-off state of the attenuator, which provides low insertion loss and high isolation. The step of the attenuator is 0.5 dB, and the attenuation range is 31.5 dB. The measurement results show a maximum root mean square (RMS) attenuation error of 0.51 dB and RMS phase error of 6.6 degrees from DC-18 GHz. The chip area is 1.8 × 0.6 mm2. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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15 pages, 4392 KiB  
Article
Design of a Modified Compact Coupler with Unwanted Harmonics Suppression for L-Band Applications
by Saeed Roshani, Salah I. Yahya, Sobhan Roshani, Amir Hossein Farahmand and Siroos Hemmati
Electronics 2022, 11(11), 1747; https://doi.org/10.3390/electronics11111747 - 31 May 2022
Cited by 8 | Viewed by 1464
Abstract
This paper presents the design, analysis, and fabrication of a new miniaturized microstrip branch line coupler (BLC) with high harmonics suppression. The T-shaped resonators, open stubs cross-shaped resonators and radial stubs are used in the proposed coupler design. The designed BLC operates at [...] Read more.
This paper presents the design, analysis, and fabrication of a new miniaturized microstrip branch line coupler (BLC) with high harmonics suppression. The T-shaped resonators, open stubs cross-shaped resonators and radial stubs are used in the proposed coupler design. The designed BLC operates at 1 GHz frequency, which can suppress up to 5th spurious harmonics with a 20 dB level of attenuation. High miniaturization of about 86% is obtained for the proposed BLC, which is corresponding to the normalized size of 0.009 λg2. The measured values of isolation and return loss are obtained 28 dB and 29 dB, respectively, while the measured insertion loss of better than 0.2 dB is achieved at the operating frequency. Additionally, the operating bandwidth of the designed coupler ranges from 0.905 GHz up to 1.105 GHz, which shows a 200 MHz operating bandwidth or a fractional bandwidth (FBW) of 20%. The presented BLC is fabricated and measured, where the measurements confirm the simulated results. The designed coupler shows desirable performance compared to the recent designed couplers. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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12 pages, 5771 KiB  
Article
Single-Ridge Waveguide Compact and Wideband Hybrid Couplers for X/Ku-Band Applications
by Guendalina Simoncini, Riccardo Rossi, Federico Alimenti and Roberto Vincenti Gatti
Electronics 2022, 11(10), 1538; https://doi.org/10.3390/electronics11101538 - 11 May 2022
Cited by 2 | Viewed by 1935
Abstract
Hybrid couplers are important devices that combine or divide signals in various microwave applications. Wideband performance, low losses and small size are key features in most modern radar and communication systems. This paper presents a new geometry for single-ridge, air-filled waveguide quadrature hybrid [...] Read more.
Hybrid couplers are important devices that combine or divide signals in various microwave applications. Wideband performance, low losses and small size are key features in most modern radar and communication systems. This paper presents a new geometry for single-ridge, air-filled waveguide quadrature hybrid couplers at the X/Ku band on a single layer using multiple pairs of slots cut on a common ridge coupling section. Bandwidth can be progressively extended by increasing the number of slot pairs. Two designs characterized by compact size and state-of-the-art performance are proposed, leading to a fractional bandwidth up to 46.88% and a maximum dimension of 1.18 wavelengths. A tolerance analysis is presented to highlight the design robustness and reliability. Full article
(This article belongs to the Special Issue Advanced RF, Microwave, and Millimeter-Wave Circuits and Systems)
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