Implementation of Slot-Coupled Broadband Butler Matrix Based on Multiple Layered Microstrip Transmission line

서지정보

· 발행기관 : 한국지식정보기술학회
· 수록지 정보 : 한국지식정보기술학회 논문지 / 12권 / 4호 / 581 ~ 590페이지
· 저자명 : 양두영, 이동학

초록

Switched beamforming network required for multiple input multiple output (MIMO) technology and smart antenna technology can adaptively adjust the beam direction of the array antenna according to the moving direction of the mobile station. Therefore, the proposed beamforming network called Butler matrix is a power feeding system capable of forming beams in various directions by adjusting the magnitude and phase of the feed signals applied to the array antenna. In this paper, a combination of microstrip slot-coupled directional couplers and slot-coupled crossovers including 45° phase shifter has been employed to expand the bandwidth of the 4x4 Butler matrix and reducing the number of conventional crossovers. The proposed slot-coupled components consist of two rectangular microstrip transmission lines (RMTLs) facing each other at the top and bottom layer and a common ground. The coupling between these RMTLs is achieved by cutting a rectangular slot in the ground plane which is located at the middle layer. A common ground is in a position between the two dielectrics. From the simulation and measurement results, the proposed Butler matrix has a good performance of broad fractional bandwidth of 43%, return loss of 15.5dB, insertion loss of 6.5±0.4dB and progressive phase shift of -45, 135, -135, 45 ±5° in 2.5~2.7GHz operating frequency band.

참고자료

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