Design of Compact Fragment-Type Antenna Array for Microwave-Based Head Imaging Application

Specifically designed antennas are needed to meet the needs of head imaging applications where an antenna array is typically used. In this article, the design of a compact fragment-type antenna using a genetic algorithm is proposed. The proposed antenna is fabricated by a low-cost FR4 substrate and covers a 72.4% fractional bandwidth (1.92 to 4.1 GHz), with an average gain of more than 2.02 dBi. The overall structure of the proposed antenna is equivalent to 0.29 λ0 × 0.19 λ0, where λ0 is the corresponding wavelength at 1.92 GHz. The results indicate that the proposed antenna is compact and suitable for microwave-based head imaging. An effective microwave head imaging system with an array of 8 compact fragment-type antennas is designed, with one antenna working as a transmitter and the others working as a receiver in turn. The imaging performance is investigated with blood layer inside the head model using the Microwave Radar- Based Imaging Toolbox open-source software. The detection of the presence and location of stroke is done by analyzing the compact fragment-type antennas’ backscattered signal.