Microwave lens using multi-layer substrates for antenna gain enhancement

A microwave lens implemented using multi-layer substrates is proposed for antenna gain enhancement. The microwave lens proposed is composed of 11 layers of parallel substrates. A 3D-patch antenna designed to operate in the frequency band from 8 to 9 GHz (S11<;-10 dB) is used for studying the microwave lens. Dual-feeding is used in the patch antenna to reduce cross polarization. For gain enhancement, the microwave lens is placed above the radiating patch of the antenna. The whole setup is studied using computer simulation. Results show that the microwave lens has little effects on the impedance bandwidth and efficiency of the patch antenna, but can increase the antenna gain by 9.4 dBi from 7 to 16.4 dBi at the frequency of 8.5 GHz.