LTCC-Based Antenna-in-Package of Dual-Linear Polarizations by Coupling Patches for 5G/LEO Broadband User Terminal Applications at mmW Frequencies

Ka-band millimeter-wave (mmW) frequencies have broad bandwidths for high data throughput in the 5th generation mobile and low-earth-orbit (LEO) satellite communications. An antenna-in-package (AiP) based antenna subarray is developed for high gain radiations benefiting high power loss compensation. The AiP is fabricated by a low-temperature co-fired ceramic (LTCC) process to provide broadband dual-polarization radiations in the broadside direction. The antenna is designed using three coupling metal patches to produce multi-resonances of reflection coefficients with high polarization isolations. Numerical full-wave simulations by HFSS show that the complete AiP of 2× antennas has bandwidths of 26.58~40.93 GHz for dual-band operations if a -10 dB reflection coefficient threshold is considered, representing a 43% bandwidth. The achieved gains are 8.5 and 12.3 dBi at 28 and 39 GHz. Experimental measurements over an antenna prototype are shown to validate the simulation designs, where the measured frequency band is 25.8~40GHz, 0.8 GHz smaller than the simulation. Due to fabrication discrepancy, the measured resonances experience frequency shifts, which, however, does not significantly reduce the bandwidth.