LTCC Differential-Fed Patch Antenna Sub-Array with Low Cross-polarization

A two-element patch antenna sub-array with low cross-polarization is proposed. Unlike conventional antenna array, the proposed array employs a novel differential via-wall feeding structure, by which it can have low cross-polarization in H-plane and symmetric radiation pattern in E-plane. The via-wall feeding structure can also enhance the bandwidth. Low-temperature co-fired ceramic (LTCC) fabrication process is adopted to realize this antenna at 13 GHz. The proposed differential antenna integrates easily with ready-made differential devices. The proposed design achieved the 10-dB impedance bandwidth of 10% and peak gain of 6.8 dBi. The simulated results also show that an excellent H-plane cross-polarization of less than -27 dB is obtained.