DESIGN AND IMPLEMENTATION OF MICROSTRIP PATCH ANTENNAS FROM NARROWBAND TO ULTRA-WIDEBAND WITH HIGH INTERPORT ISOLATION FOR IN BAND FULL DUPLEX COMMUNICATION SYSTEMS

Lütfi Yiğit Erol
Electronics Engineering, MSc. Thesis, 2020

Thesis Jury

Prof. Dr. İbrahim Tekin (Thesis Advisor), Assoc. Prof. Dr. Hüsnü Yenigün, and

Assoc. Prof. Dr. Nurhan Türker Tokan

Date & Time: August 17th, 2020 – 10.00 AM

Place: Zoom Meeting – 983 294 570

Keywords: In band full duplex communication, self-interference cancellation, microstrip patch antenna, differentiation circuit, high isolation, ultra-wideband, balun

Abstract

In band full duplex (IBFD) operation is one of the attractive solutions to enhance the spectral efficiency and the throughput of wireless communication systems and networks. One of the best advantages of IBFD is to receive and transmit RF signals simultaneously at the same frequency band. However, there are many challenges for implementation of IBFD operation; one of them is self-interference (SI).

In general, the improvement of the spectral efficiency and the throughput of a communication system is directly proportional to high signal to noise ratio (SNR). To achieve a high SNR value, SI should be suppressed to noise floor. In IBFD communication systems, most of the SI cancellation is provided at antenna stage. Thereby, the implementation of an antenna with very high isolation offers a great solution for IBFD communication systems.

In this thesis, the microstrip patch antennas from narrowband to ultra-wideband are designed and implemented to use in IBFD operation. The implemented 2.4 GHz and 5.9 GHz IBFD differential fed microstrip patch antenna arrays and 2.4 GHz IBFD double differential fed microstrip patch antenna achieve interport isolation of 53, 51 and 62 dB over their operating bandwidths of 50, 200 and 50 MHz, respectively. On the other hand, the implemented ultra-wideband (UWB) IBFD antenna provides interport isolation of 30 dB for its 4.9 GHz of 10 dB return loss bandwidth (2.3 – 7.2 GHz). This antenna may be used for all of Wi-Fi bands including the next generation IEEE 802.11be whose possible need will be full-duplexity.