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.

A novel probe fed right hand circularly polarized (RHCP) shared aperture antenna with concentric configuration is designed for L5 and S-bands NavIC receiver application. The structure consists of a square loop-type patch antenna for the L5 band, serves as the top radiator, and a concentrically truncated corner patch antenna for the S-band is embedded in the non-radiating portion of the L5 band antenna. The square loop is orthogonally fed with electromagnetically coupled strips with equal power and quadrature phased shift through symmetric vias. These vias are connected to the feeding network, which consists of a Wilkinson power divider that is designed on opposite sides of the ground to mitigate spurious radiations. Furthermore, the S-band antenna, placed inside the L5 band substrate, achieves CP by corner truncation. This technique increases the aperture reuse efficiency and improves the isolation between both radiators. The overall profile of the antenna is 75×75×8mm3 and exhibits a wide impedance bandwidth of 25.5% for the L5 band and 6.5% for the S-band, with an isolation of better than 20dB for both bands. The axial ratio bandwidth achieved is 25.5% and 4.1% for the L5 and S bands, respectively, with boresight gain of 3.57 dBiC and 4.8 dBiC in the L5 band and S-band, respectively. The proposed antenna is based on a shared aperture technique, which has different feeding ports for both bands; thus, it improves the G/T performance and noise figure of the overall system. These characteristics make the proposed antenna suitable for use in NavIC application.

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.

This paper presents a single-stage amplifier using substrate-integrated coaxial line (SICL) technology. It is implemented with a low-cost PCB technique at 23.35–24.05 GHz. The size of the proposed amplifier is 4.9λg×1.1λg where λg is the guided wavelength at the center frequency. In this circuit, a SICL-based bias-tee network is designed where the mounting pads are introduced for the integration of the components, such as transistor and capacitor. Next, with the help of de-embedding techniques, the input and output matching networks are designed in the SICL environment at 24 GHz. The proposed amplifier circuit exhibits 9.2 dB of peak gain with less than 1 dB of gain ripple and more than 10 dB of input/output return losses in the operating frequency band of 23.35–24.05 GHz. Moreover, the elementary blocks of the amplifier are presented in the circuit. Based on the appropriate modeling of the amplifier's elementary blocks, the simulated and measured results are in good agreement.

This article presents the modeling and realization of a compact substrate integrated coaxial line (SICL) based butler matrix operating at 5 GHz for beam-forming applications. The proposed 4 × 4 butler matrix is developed using SICL-based hybrid coupler, crossover, and phase shifter. A compact 90° coupler comprising of center tapped unequal stubs is designed to enhance the size reduction as well as to extend the out of band rejection. Wideband SICL-based crossover operating from DC to 10 GHz is conceived for the proposed butler matrix using a plated through hole as transition. The SICL crossover features very high measured isolation of 65 dB owing to the reduction in coupling between the two signal paths within a lateral footprint of only 0.034. A meandered SICL-based line is used in order to provide the necessary 45° and 0° phase shift to realize the butler matrix. The fully shielded and self-packaged compact 4 × 4 SICL-based butler matrix is fabricated and experimentally validated to operate at 5 GHz.

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.