This paper proposes a new two-dimensional (2D) Butler matrix antenna array with 16 switching beams for tile-based beamforming. This study fabricated and assembled a 3.5-GHz Butler switching antenna array using multilayer Rogers printed circuit board technology. It adopted a new design concept and layer-by-layer vertical connection architecture. This 2D Butler matrix antenna array does not require long coaxial cables to connect functional circuit interfaces, which is an improvement over the traditional Butler matrix beamforming network (BFN) antenna array and may facilitate considerable reductions in circuit volume and complexity.
This letter proposes a UHF lowpass filter based on the image parameter method. This study designed, fabricated and assembled a 0.48-GHz semilumped lowpass filter using low cost FR4 substrate. It adopted a new layout concept for the air wound coils to achieve the purposes of compact size and good performances. The proposed UHF lowpass filter has the best performances for the roll-off rate and circuit size compared to previous works, and it also achieves the best figure of merit 973,369.
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