High-gain low-cross-polarization 60-GHz LTCC patch antenna array with differential-fed and soft-surface structures

Abstract

A 2×2 60-GHz differential-fed patch antenna array was developed using low-temperature co-fired ceramic (LTCC) multilayer technology with high gain and low cross-polarization level. The antenna elements were constructed by radiation patches and folded L-shaped feeds. A novel soft-surface structure was designed to suppress the surface wave and enhance antenna gain. Substrate-integrated waveguide (SIW) and differential-fed structures were applied to reduce the loss of feeding network and the cross polarization level. The proposed antenna array achieves flat gain curve over the range of 55–65 GHz with a peak gain of 13.6 dBi at 62.1 GHz. The simulated cross polarization level was lower than −35 dB in both E-plane and H-plane.