A compact switched beam-forming network using silicon IPD technology for low-cost 5G communication

This paper introduces a compact and single-packaged beam forming network for a low-cost 5G transceiver system. For low-cost, silicon IPD (integrated passive device) is used to make the 4 × 4 Butler matrix and a switch IC is embedded in the silicon to make a single package structure and wire-bonding can be removed. The conventional branch line coupler is modified to minimize its size using MIM capacitors and short transmission lines. The measured result shows RMS magnitude errors are less than 0.96 dB and RMS phase errors are less than 10° at 28.7-30.6 GHz. Total area of the Butler matrix, pads not included, is 3 × 2.5 mm
²
and the size of the final module including the switch IC is 6.7 × 3.3 × 0.1 mm
³
.