A Dual-Band Dual-Polarized 2×2 Antenna Array with Beamforming for 5G AiP and mmWave Applications

In this study, we present a dual-band (28/39GHz) 2 by 2 antenna array design on a 10(4+2+4) multi-layer organic substrate with broad bandwidth and higher isolation onto a compact AiP module. In addition, the H-type slot antenna structure can improve interference and isolation between 28 and 39GHz bands. The measured result shows the isolation can larger than 15dB between low and high band. For antenna measurement, the spherical of probing chamber is utilized to validate 28/39GHz antenna pattern and performance with a package level passive testing. Our AiP measured result shows the return loss is better than 10 dB in 23.5-30.5 GHz range, with ~7 GHz bandwidth and provides a high-gain per element (above, 6 dBi) radiation pattern for 28GHz applications. For 39GHz band, the antenna has 7 GHz bandwidth and provides a 5 dBi gain between 38–45 GHz. Comparison of S-parameter between simulated and measured results, there is a good correlation to obtain the quality of manufacturing. Furthermore, a 28GHz beamforming array is designed and demonstrated. The beamfoming array consists of a four-channel transceiver with 2 × 2 antenna array. The beamformer IC is implemented by TSMC 90-nm CMOS technology and the flip-chip bonded on BT substrate. For beamforming test, an integrated socket and load board are designed for support the mmWave module and then connection between DUT and test system. The load board substrate includes the IF, LO, and DC distribution network for respectively. There are 4-channel transmit beamforming array front-end module for testing. Finally, the 3D beam steering of 2 by 2 antenna array is measured with multi-states at 28 GHz, with a maximum realized gain of 11.8 dBi achieved in the main beam (θ=0°). It shows that beamforming can be generated at a specific beam direction by controlling the phase of the signal in each antenna element.