Mukherjee, Soumava

This research letter introduces a multiple-input-multiple-output antenna array for simultaneous operation in 5G FR2 millimeter-wave and 6G midband frequencies. At 10 GHz, a substrate integrated waveguide cavity backed slot antenna (CBSA) is designed to radiate in the broadside direction with a gain of 6.3 dBi. A rhombus-shaped slot is engraved on the top layer of the cavity and its position is tuned to obtain a bandwidth of 750 MHz to satisfy the forthcoming 6G midband. At 28 GHz, a substrate integrated coaxial line (SICL) fed novel pm45circ inclined crossed dipole antenna exhibiting a gain of 6 dBi is designed. An impedance matching network is designed in the middle layer to achieve a bandwidth of 3.5 GHz, enabling support for the entire n261 and n257 bands of the FR2 millimeter-wave frequency. In order to have simultaneous operation at 10 and 28 GHz, a novel SICL transmission line-based feed section is proposed. In the lower band (10 GHz), one arm of the feed section feeding the crossed dipole behaves as an open-circuited line, facilitating wave propagation exclusively in the lower band CBSA. Similar effect is obtained in the other arm for operation in the upper band (28 GHz). This technique helps in attaining simultaneous 5G/6G performance while having negligible effect at the other operating frequency.

In this paper, a broadband and high gain substrate integrated waveguide (SIW) cavity-backed slot antenna has been developed with a stacked configuration. The proposed antenna comprises a rectangular cavity with a bow-tie slot, an SIW, a microstrip line-to-SIW transition, and a stacked parasitic patch. An additional resonance is created at a higher frequency by properly optimizing the parasitic patch above the cavity-backed slot, improving the bandwidth and gain significantly. Compared with the SIW cavity-backed slot antenna, the impedance bandwidth and peak gain are increased from 5.12% (for |S11|≤slant - 10 dB) to 19.7% and 7.4 to 8.67 dBi, respectively. The overall size of the proposed antenna is 14 mm × 12 mm × 0.85 mm. The proposed design technique is easy to implement and promises to overcome the limitation of the narrow bandwidth of cavity-backed slot antenna without increasing its overall footprint.

In this paper, the feasibility of antenna arrays has been studied for wide/multi-band base station massive multiple- input-multiple-output (MIMO) systems in millimeter-wave band according to requirements of 3GPP TR 38.877. Base stations utilize special beamforming with uniform phased array antennas on numerous panels to serve many users. An 8-panel massive MIMO antenna system is designed with a 4x4 phased antenna array for a wide bandwidth of almost 42.2%, supporting n257 /n261 +n260 or n258+n260 band combinations. It achieves a peak gain of a minimum of 17 dBi and a scanning range of ±40° with sidelobes lower than 9.4 dB. The minimum isolation of 17 dB is achieved between the adjacent antenna elements with the use of a decoupling method. The diversity parameters envelope correlation coefficient (ECC) and diversity gain (DG) remain better than 0.007 and 9.9997 dB, respectively, over the entire operating bandwidth for different steering angles, showing a good MIMO performance.

In this study, a novel and compact substrate integrated broadband Dielectric Resonator Antenna (DRA) excited by Substrate Integrated Coaxial Line (SICL) is presented. In comparison to the traditional non-planar DRA configuration, that requires mounting of a dielectric over the feed, the presented work provides a simple alternative by utilizing the same substrate of the SICL feed network making it planar. This eliminates the major challenge of a complex fabrication process in designing DRA. Two semi-circular rings fed by the top and middle layer of SICL feed line forms the resonating structure of the DRA, exhibiting a bandwidth of 550 MHz. The design procedure is shown to enhance the bandwidth to 1.3 GHz of the proposed antenna. The field distribution attained in the suggested Dielectric Resonator Antenna (DRA) has similarities to the HEM12δ mode of the standard cylindrical DRA. The proposed DRA achieves a broadside unidirectional beam with a gain of 5.5 dBi at 26 GHz.

This paper presents a Ka-band series single-pole double-throw (SPDT) switch circuit realized in substrate-integrated coaxial line (SICL) environment for time division duplex operation. It is designed with a low-cost printed circuit board (PCB) technique. The size of the proposed circuit is, where λg is the guided wavelength at the center frequency of 27.75 GHz. In this circuit, a SICL-based SPDT switching circuit is proposed with radio frequency (RF) isolation network where the shunt connection of butterfly stubs is in an asymmetric stripline environment. The proposed circuit exhibits less than 2 dB insertion loss at 27-27.9 GHz and less than 2.5 dB insertion loss at 27-28.5 GHz. The design offers good impedance matching in the Transmit (Tx) and Receive (Rx) channels from the common Tx/Rx input channel, along with more than 24 dB isolation between ON and OFF state output channels. The proposed circuit is suitable for millimeter-wave communication systems.

In this paper, a novel design of half-mode substrate integrated waveguide (HMSIW) cavity based antenna is presented for dual-frequency application in Ka band (26-40 GHz). Two HMSIW cavities are placed side by side and are excited through the help of inductive coupling window followed by a section of HMSIW line. As a result, the cavities are excited at TE110HM mode and the open end dielectric aperture of the HMSIW cavity starts radiating into free space. The two HMSIW line are connected to the input SIW feeding line with the help of a SIW to HMSIW power divider. The proposed antenna resonates at 26 GHz and 29 GHz while maintaining a compact design configuration which makes it suitable for application in LMDS frequency band.

The design of Substrate Integrated Coaxial Line (SICL) based wideband baluns for K-band application are presented in this work. The proposed two-section branch-line balun realized in SICL technology can be fabricated using traditional PCB technology. The performance of the planar and folded balun are evaluated to demonstrate low amplitude and phase imbalance in the entire K-band covering 18 GHz to 26 GHz. Fractional bandwidth of 40.68% and 37.27% are achieved by the proposed planar and folded balun, respectively. The size of planar SICL balun is 0.73λg × 0.78λg × 0.05λg, and the folded balun covers only 58% lateral area as compared to the planar balun. The wide-band single mode TEM characteristics of these baluns realized in SICL technology have enhanced shielding capability which motivates their usage in densely integrated millimeter-wave systems.

In this work, a novel dual-mode Substrate Integrated Coaxial Line (SICL) based bandpass filter operating at 28 GHz, targeted for 5G application is conceived. The proposed dual-mode bandpass filter is realized by exciting the degenerate modes in a corner-cut middle layer square patch by etching cross-shaped slots. The proposed filter exhibits a 12.25% 3-dB fractional bandwidth with a maximum 0.42 dB insertion loss in the passband. Frequency selectivity is enhanced by a transmission zero at 33.8 GHz which extends the out of band rejection up to at least 40 GHz. Further, the proposed SICL based cavity demonstrates a 46.75% size reduction as compared to its Substrate Integrated waveguide (SIW) counterpart. The superior electromagnetic compatibility of the proposed miniaturized SICL based dual-mode bandpass filter makes it an attractive option to deploy in millimeter-wave range.

In this paper, design of Substrate Integrated Coaxial Line (SICL) based four way power divider is presented. A detailed study of different configurations of power divider based on SICL technology is explored. To realize impedance matching at the three port junctions, SICL based quarter wave impedance transformer is used in both Tee and Y type power divider. Both the designs exhibit equal power division with output power within the range of-3 0.05dB. The phase difference between the output ports of the two way power divider is below 0.5°. A design of SICL 90° bend is also studied. To compensate the reactive loading effect at the bend, chamfering at the central conductor is implemented which helps to improve the S parameter performance of the design. Finally, the Tee and Y power divider is cascaded along with SICL bend to realize SICL four way equal power divider. The proposed design operates over entire K band (18-26 GHz) with its reflection coefficient below-16 dB. The output power of the design is within-6 0.55 dB and the phase difference between the output ports are below 0.9°. The proposed design is compact in size and exhibits broad bandwidth making it suitable for practical applications.

This article, presents a novel technique to model a wideband coaxial to substrate integrated coaxial line (SICL) transition. The proposed design is a planar implementation of the male to female connection usually observed in coaxial connections in conventional circuit. Firstly, a 50\ \Omega SICL section is designed. The coaxial probe of equal impedance passing through a metallic via with slightly greater diameter is then connected to the inner conductor of SICL. The reactive component produced at the SICL-Coaxial junction is nullified by placing a short-circuit section at an optimal distance from it. The proposed transition demonstrates a broadband matching of greater than 20 dB for 0 to 32.7 GHz with very low insertion loss of better than 0.1 dB throughout the band. The complete modeling of proposed planar transition is presented and the robustness of the design is validated for different dielectric constant and thickness. The designed back to back transition exhibits wideband matching with very low insertion loss making it worthy for practical applications.