Highly Integrated Switched Beamformer Module for 2.4-GHz Wireless Transceiver Application

In this paper, a miniature switched beamformer module for 2.4-GHz applications is proposed. The proposed beamformer module is based on the integrated passive device technology, and it integrates a 4 x 4 Butler matrix, a singlepole four-throw beam-selection switch, and a p-i-n diode-based transmit/receive (T/R) switch into a compact module size of only 4.9 mm x 5 mm x 0.9 mm. To achieve the compact module size, bridged-T coils are used to replace the transmission line sections in the 4 x 4 Butler matrix and the T/R switch. The measured insertion loss at the center frequency of 2.4 GHz is within 10.89 +/- 1.13 dB for the receive path and 11.33 +/- 0.69 dB for the transmit path. The measured phase error is less than 8.4 degrees at 2.4 GHz. The proposed beamformer features low cost, compact size, and low profile. It can help enable the use of phased array technique in handheld mobile devices.