Search Results (7)

A low-profile dual-polarized shared-aperture phased array antenna is proposed for Ku-band satellite communications in this paper. The stacked octagonal patches loaded with Via-rings are proposed as dual-polarized shared-aperture radiation elements, with the characteristics of wide impedance bandwidth, high gain, and weak coupling. Furthermore, innovative minimized three-port ring couplers are utilized for the differential-fed antenna array, further suppressing the cross-polarization component. Substrate integrated coaxial line (SICL) and microstrip line (MS) feed networks are employed for the excitation of transmitting band (Tx) horizontal polarization and receiving band (Rx) vertical polarization, respectively. The non-uniform subarray architecture is optimized to minimize the sidelobe levels with the reduced number of transmitter and receiver (T/R) radio frequency phase-shifting modules. As proof-of-concept examples, 16 × 24 and 32 × 24 array antennas are demonstrated and fabricated. The measured impedance bandwidths of the proposed phased array antennas are around 21.1%, while the in-band isolations are above 36.7 dB. Gains up to 29 dBi and 32.4 dBi are performed by two prototypes separately. In addition, the T/R phase-shifting modules are utilized to validate the beam-scanning characteristic, which is of value for dynamic satellite communications. Full article

Power consumption in interconnects is a critical constraint on performance improvements in integrated circuits. This paper proposes a novel design methodology to minimize loss in interconnects and address this limitation. The approach incorporates air cavities within the substrate to lower the equivalent loss tangent, thereby reducing dielectric losses. Additionally, the inner conductor is engineered with a periodically nonuniform width to maintain stable effective characteristic impedance. To validate the effectiveness of the methodology, it is applied to both a substrate integrated coaxial line (SICL) and a stripline. Simulation results reveal a 9.76% reduction in loss for the SICL and a 19.40% reduction in loss for the stripline, demonstrating significant improvements with wide tolerance. Furthermore, this design methodology can be generalized to other interconnect types, offering the potential for additional power savings. Full article

A compact and wideband beamforming antenna array based on a substrate-integrated coaxial line (SICL) Butler matrix at 60 GHz is proposed in this paper. The cavity-backed patch antenna loading double-ridged horn antenna is designed to enhance a gain of 5.4 dB and a bandwidth of 2.7 GHz. Different phase centers of double-ridged horn elements are formed into a non-uniform array to reduce sidelobes by −7.9 dB. By introducing the defected ground structure (DGS) for a broadband coupler, a rotationally symmetric SICL Butler matrix is designed with a 55–70 GHz bandwidth and compact dimensions of 63 × 65 × 0.512 mm³. To validate the design, a prototype was fabricated and measured. The experimental results show a wideband −10 dB impedance bandwidth of 23.3% (55.4–70 GHz) with measured gains ranging from 15 to 16.1 dBi at 62 GHz. The one-dimensional beam scanning covers ±32°. The simulation and measurement results are in good agreement. Full article

This work presents a design for a complementary antenna with circular polarization that has a wide operating bandwidth, stable broadside radiation, and stable gain for X-band applications. The proposed antenna consists of an irregular loop and a parasitic electric dipole, which work together to produce equivalent radiation from the magnetic and electric dipoles. By arranging the dipole and the loop in a specific geometry, this antenna effectively generates circularly polarized wave propagation. A substrate integrated coaxial line (SICL) is applied to feed the antenna through an aperture cutting on the ground. The proposed antenna achieves a wide axial ratio (AR) and impedance bandwidths of 27.4% (from 8.5 to 11.22 GHz, for the AR ≤ 3 dB) and 39.6% (from 7.5 to 11.2 GHz, for the reflection coefficient ≤ −10 dB), respectively. Moreover, the antenna maintains a stable broadside radiation pattern across the operating bandwidth, with an average gain of 10 dBic. This proposed antenna design is competitive for X-band wireless communications. Full article

In this paper, a dual-band integrated bandpass filter (DI-BPF) based on a mode composite substrate integrated coaxial line (MCSICL) is proposed for a large frequency ratio. The low-frequency bandpass filter is formed by incorporating an SICL line and a gap into the MCSICL, operating in the fundamental mode of the MCSICL. The high-frequency bandpass filter is formed by introducing grounded vias into the MCSICL, operating in the first high-order mode of the MCSICL. To guide the design, the equivalent circuit models of the low- and high-frequency bandpass filters are built. Based on the equivalent circuit models, the DI-BPF is synthesized for a large frequency ratio. The transitions from the DI-BPF to ground coplanar waveguides (GCPWs) are designed for the low- and high-frequency bandpass filters. The DI-BPF with the transitions is fabricated by the printed circuit board (PCB) process. Measurement results indicate a large frequency ratio of 23.16, with the isolation between the low- and high-frequency bandpass filters exceeding 30 dB from dc to 50 GHz. Full article

High-band allocations in the millimeter-wave (mm-Wave) frequency spectrum offer high-capacity wireless information transmission as required by fifth generation (5G) communication standards. Among different beamforming structures, the Rotman lens (RL) is an attractive passive-microwave-lens-based beamforming network due to its low fabrication cost, reliability, design simplicity and wide-angle scanning capabilities. Conventionally, the RL is implemented using microstrip line (MSL) technology for which there are inherent radiation losses that become severe when operating in mm-Wave 5G frequency bands. In this context, a novel substrate-integrated coaxial line (SICL)-based RL is designed, fabricated and tested, for accurate beamforming with extremely low feed line insertion loss. This article presents a complete design, development and performance analysis of an SICL-based RL beamformer. By using an SICL, isolation of up to 15 dB is achieved between the input beam ports of the RL, while the mutual coupling is kept at less than 20 dB. The SICL design shows a −10 dB insertion loss between the array and beam ports when compared to the same RL developed using MSL technology having an insertion loss of −15 dB. Due to the use of low-loss SICL technology, a realized gain of up to 14.2 dBi is achieved with an excellent scanning capability of −30 to 30 degrees, verifying for the first time the beamforming capabilities associated with SICL technology. The operational frequency band is 20–45 GHz, while the center operating frequency is 26 GHz making it appropriate for above 6-GHz 5G New Radio (NR) operating bands n257 (26.5 GHz to 29.5 GHz), n258 (24.25 GHz to 27.5 GHz), n261 (27.5 GHz to 28.35 GHz) and n260 (37 GHz to 40 GHz). Owing to the low-loss and stable beamforming performance, the SICL RL is suitable for mm-Wave 5G and is extendable to B5G applications. Full article

When designing a microwave circuit involving substrate integrated coaxial lines (SICLs), it is important to know what real crosstalk between SICLs is. A measured crosstalk will be a good reference value in a practical design. In addition, it is also needed to compare and check the crosstalk from the simulation and calculation formula with measured results. However, it is very difficult to measure the crosstalk between SICLs because it is theoretically very low. In this study, for the first time, the crosstalk characteristics of a SICL are evaluated through experimental design and measurements. By adjusting the layout of the structures and implementing controlled experiments, interference caused by the presence of leaks and radiation at the interface and structural transitions is effectively suppressed. The experimental results show that for two parallel SICLs with a length of 30 mm and an interval of 5 mm, the isolation is greater than 80 dB for the measured frequency range of 1–8 GHz, significantly better than the results of the grounded coplanar waveguide (GCPW). Full article