Miniature 2.4-GHz Switched Beamformer Module in IPD and Its Application to Very-Low-Profile 1D and 2D Scanning Antenna Arrays

摘要

In this paper, a miniature 2.4-GHz switched beamformer module is proposed. The proposed switched beamformer module is based on the integrated passive device (IPD) technology, and it integrates a 4 × 4 Butler matrix and an absorptive single-pole four-throw (SP4T) beam-selection switch into a compact module size of only 4.9 mm × 5.0 mm × 0.4 mm. The compact module size is achieved by using bridged-T coils to replace transmission line sections in the 4 × 4 Butler matrix and the absorptive SP4T switch. The measured insertion loss of the switched beamformer module is within 9.67±0.88 dB at 2.4 GHz while the measured input/output return losses are all better than 16.9 dB. In addition, the measured phase error is less than 9.3° at 2.4 GHz. The proposed switched beamformer is then utilized to realize very-low-profile 2.4-GHz 4×1 and 4×4 scanning antenna arrays to achieve 1D and 2D beam steering, respectively.