Event date:
Sep 2 2021 2:00 pm

High Isolation Compact Antenna Arrays for Next Generation Navigation & Communication Systems

Dr. Wasif Tanveer Khan
Abdullah Madni
EE Board Room Maxwells Wing SBASSE
PhD Synopsis defense
Global Navigation Satellite Systems (GNSS) play an important part in applications such as aviation, maritime navigation, Unmanned Aerial Vehicles (UAVs) and global transportation. Major GNSS services include GPS, Galileo, BeiDou and GLONASS satellite systems. These services are divided into different frequency sub-bands ranging from 1.17642 GHz to 1.610 GHz. In this thesis, we will be focusing on the upper L- band which consists of GPS L1 (1.575 GHz), Galileo E1 (1.57542 GHz), BeiDou B1 (1.561098 GHz) and GLONASS G1 (1.602 GHz) bands covering a wide frequency spectrum from 1.561098 – 1.610 GHz. This frequency band is used for Aviation Radio Navigation Service (ARNS) and Radio Navigation Satellite Service (RNSS).

GNSS satellites are located hundreds of kilometers away from the earth. Due to such a large distance, GNSS signals become very weak when they reach the earth and are vulnerable to jamming and interference. As a result, the satellite signals are masked with noise resulting in signal loss. This can be mitigated by designing antenna arrays capable of creating nulls in the direction of potential jammers. In addition to this technique, designing an antenna array which is wideband and covers multiple GNSS bands will minimize the effect of jamming as if one frequency band is jammed then the array will still be able to receive the signal in the other GNSS frequency bands. Designing such antenna arrays is a challenging task as the mutual coupling between antenna elements and compactness must be taken into account.

In this thesis/PhD proposal, we address the problem of mutual coupling by presenting new techniques to increase the inter-element isolation in a compact four element antenna array designed on a high epsilon material. Our proposed design is wideband and covers all the four major GNSS services in the entire GNSS upper L-band (1.561 – 1.610 GHz) with an isolation of more than 20 dB within a compact diameter of only 125 mm. We have also analyzed the performance of our design on the basis of substrate permittivity, size, radiation, efficiency and gain. The designs are validated by simulations and also backed by theory. The design process and critical parameters are also explained in this research. We have also addressed the issue of compactness and miniaturization by proposing the addition of slots in the patch antenna and employing a substrate of higher permittivity. Furthermore, the extension of four element antenna array to seven and eight element antenna arrays is also proposed backed by some preliminary design layouts.