A Phase Distribution Network Using 2 × 4 Butler Matrix for Linear/Planar Beam-Scanning Arrays

Abstract

A new 1  4 phase distribution network (PDN) featuring a fully controllable progressive phase shift between outputs is proposed for continuous beam-scanning arrays. The PDN is made up of two parts: a modified 2  4 Butler matrix integrated with four phase shifters (PSs), and a tunable power divider (TPD) whose power division ratio can be controlled over a wide tuning range. The synthesis equations show that the relative phase shift between PDN outputs can be fully controlled by the TPD and embedded PSs without using an external single-pole quad-throw (SP4T) switch. The proposed PDN is demonstrated at 2.4 GHz as the feed network of a 4-element linear array. The experimental results display a fully controllable progressive phase shift (from −180° to 180°) between PDN outputs over a 20% bandwidth with good performance of matching, power division, and relative phase shifts. A spatial coverage of 116° with the feature of continuous beam scanning and negligible dc power consumption is achieved. Benefitting from the single-input topology, a planar 16-element phased array for 2D beam scanning is then realized by simply stacking and cascading five instead of eight PDN modules. It removes the high-cost and bulky SP16T switch. Experimental results demonstrate the uniqueness of the proposed designs.INDEX TERMS Antenna arrays, beam-steering, Butler matrix, phase shifters, tunable circuit and devices.

A novel 4 × 4 butler matrix with continuously tunable phase covering 360° range and application for 1‐D and 2‐D beam scanning array

“…Butler matrix (BM) is one of the most classic circuit-based beam-forming networks (BFNs). Recently, BM has been widely adopted, researched and modified in the literature because of its simplicity, low-cost and easy realisation [1][2][3][4][5][6][7][8][9][10][11][12]. A typical 4 � 4 BM can feed a linear antenna array to generate four beams in different direction.…”

“…Therefore, some BMs with continuous beam steering capability have been proposed in refs. [7][8][9][10][11]. In ref.…”

“…Similarly, a tunable power divider with tuning power division ratio was adopted to achieve fully controllable progressive phase shift between outputs in ref. [9]. However, the proposed BMs in refs.…”

“…However, the proposed BMs in refs. [8,9] introduced signal amplitude control network which increased the complexity of BFNs. In summary, these aforementioned BMs used for feeding linear antenna array have drawbacks like discontinuously tunable output phase difference [2][3][4][5][6], narrow tuning range [7], relatively complex mechanism and structure [8,9] etc.…”

“…As compared to the proposed BMs in refs. [8,9], the proposed design does not require complex amplitude control network which can significantly the design difficulty and complexity. Therefore, the proposed BM can be used to feed a linear 1-D array or a 2-D planar antenna array with continuous beam scanning capability.…”