H-slot fed patch antenna with frequency duplex function using band stop filter

A H-slot fed patch antenna with frequency duplex function using band stop filter is presented. The proposed antenna consists of two ports, one is used for transmitting (TX), and the other is for receiving (RX). To improve the TX-RX isolation, two stub band stop filters are added to the feeding lines. The antenna is fed through two different H slots to achieve transmitting and receiving frequency operations. Also, the antenna has horizontal polarization for each operating frequency band. Experimental results show that the isolation is less than 40dB at 2.18GHz and 2.78GHz.