A Compact Magneto-Electric Dipole Antenna for S-Band MIMO Through-Wall Radar

In order to achieve sufficient penetration depth, the antennas for through-wall radar require low operating frequency, small size, and high gain. In this paper, an ultra-wideband and low-cost magneto-electric (ME) dipole antenna operating in the S-band for through-wall radar application is proposed. A size reduction structure is achieved by proposing a Minkowski-like fractal ground in conjunction with a folded shorted patch to increase the path of the surface equivalent current. Moreover, this structure can be easily machined using multilayer printed circuit board (PCB) with low cost. Test results show that the final prototype has an impedance bandwidth of 66.7% in the frequency range of 1.7 ~ 3.4 GHz and the peak gain in the frequency range is 7.73 dBi, while maintaining a stable radiation pattern across its entire frequency band. The antenna features a wide bandwidth, compact design, high gain, and low cost, making it suitable for the demanding through-wall applications. The performance of the antenna is compared with the state-of-the-art works to demonstrate its key advantages over similar designs. Additionally, it has been seamlessly integrated into a Frequency Modulation Continuous Wave (FMCW) radar system, where it has undergone practical testing and achieved outstanding detection performance.