| dc.description.abstract | Phased arrays have been gradually applied to wireless communication systems in our daily life. Among various phased array technologies, the switched beamformers are relatively easy to realize, and they are more suitable for commercial wireless communication systems due to their low power consumption and low cost. In this study, two 2.4-GHz switched beamformer modules in IPD process with low power consumption and compact size are proposed, which are targeted for implementing smart antenna systems in mobile communication devices.
The Bridged-T coil is the core technology used in this study. Specifically, the bridged-T coil is adopted to realize the building blocks of the proposed switched beamformer such that very compact circuit size can be achieved. The use of the bridged-T coil to achieve circuit size reduction of microwave circuits is first demonstrated by an ultra-wideband multi-mode resonator bandpass filter design. The smallest multi-mode resonator bandpass filter ever reported is presented.
Next, the bridged-T coils are used to realize the key building blocks of a 2.4-GHz switched beamformer modules, i.e., an absorptive single-pole double-throw (SPDT) switch, a T/R switch, and a 4 × 4 Butler matrix. By replacing the transmission line sections with bridged-T coils, the chip sizes of these circuit elements are largely reduced. Two switched beamformer modules are then realized based on the heterogeneous integration of these building blocks. The first one integrates a 4 × 4 Butler matrix, an absorptive SP4T switch, and a T/R switch in a compact module size of 4.9 mm × 5.0 mm ×0.9 mm. The second one integrates a 4 × 4 Butler matrix and two absorptive SPDT switches, which features a module size of 4.9 mm × 5.0 mm with a very low profile of only 0.4 mm.
In additional, dual-band bridged-T coil is proposed to help achieve miniature dual-band beamformer designs. A dual-band branch-coupler is first implemented in IPD process, which is the smallest dual-band branch-line coupler ever reported. Then, a dual-band 4 × 4 Butler matrix is designed for 2.45/5.8-GHz dual-band switched beamformer applications. The proposed switched beamformer modules feature low-cost, compact size, low power consumption, and low-profile. They can help introduce smart antenna systems into modern mobile applications. | en_US |