scholarly journals Substrate Integrated Waveguide Antenna System for 5G In-Band Full Duplex Applications

Electronics ◽  
2021 ◽  
Vol 10 (20) ◽  
pp. 2456
Author(s):  
Masaud Shah ◽  
Hammad M. Cheema ◽  
Qammer H. Abbasi
Keyword(s):  
Spectral Efficiency ◽  
Interference Cancellation ◽  
Phase Shifter ◽  
Antenna System ◽  
Full Duplex ◽  
Power Combiner ◽  
New Approach ◽  
Mode Of Operation ◽  
Duplex Systems ◽  
Better Than

In-band full duplex offers a new approach of meeting the ever-increasing data rate demands by operating the transmitter and receiver at the same frequency at the same time, potentially doubling the spectral efficiency. However, self-interference is the fundamental bottleneck of such systems. In contrast to non-planar or sub 6 GHz microstrip designs reported so-far, this paper presents an all SIW based antenna system for in-band full duplex systems. The proposed design integrates a dual linear polarized three port differential antenna, three port SIW common-mode power combiner and a 180°phase shifter at 28 GHz. Operating the antenna in TE201 mode provides inherent isolation between the differential receive and single-ended transmit port. The residual coupling is further reduced through use of TE101 based power combiner and a 180°phase shifter. Implemented on a 0.508 mm thick RT Duroid 5880 substrate, the antenna occupies a foot-print of 48 × 80 mm2. Demonstrating a measured gain of 6.95 dBi and 3.42 dBi for Tx and Rx mode of operation, respectively, the proposed design offers a self-interference cancellation (SiC) of better than 36 dB over a 177 MHz bandwidth.

A tuneable rat-race coupler for full duplex communications

2021 ◽  
pp. 1-7
Author(s):  
G. T. Watkins
Keyword(s):  
Interference Cancellation ◽  
Phase Shifter ◽  
Dipole Antenna ◽  
Full Duplex ◽  
Frequency Channel ◽  
Ism Band ◽  
Single Antenna ◽  
Variable Attenuator ◽  
Degree Of Isolation ◽  
Better Than

Abstract Full duplex (FD) could potentially double wireless communications capacity by allowing simultaneous transmission and reception on the same frequency channel. A single antenna architecture is proposed here based on a modified rat-race coupler to couple the transmit and receive paths to the antenna while providing a degree of isolation. To allow the self-interference cancellation (SiC) to be maximized, the rat-race coupler was made tuneable. This compensated for both the limited isolation of the rat race and self-interference caused by antenna mismatch. Tuneable operation was achieved by removing the fourth port of the rat race and inserting a variable attenuator and variable phase shifter into the loop. In simulation with a 50 Ω load on the antenna port, better than −65 dB narrowband SiC was achieved over the whole 2.45 GHz industrial, scientific and medical (ISM) band. Inserting the S-parameters of a commercially available sleeve dipole antenna into the simulation, better than −57 dB narrowband SiC could be tuned over the whole band. Practically, better than −58 dB narrowband tuneable SiC was achieved with a practical antenna. When excited with a 20 MHz Wi-Fi signal, −42 dB average SiC could be achieved with the antenna.

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