Design of Via-Hole for Dual Layer Butler Matrix

This paper presents a dual layer butler matrix for 5G wireless communication at 28 GHz using via-hole. Via-hole is proposed as the phase shifter connecting dual layer substrate Butler Matrix. In this design, two sides of the substrate are stacked to minimize the occupied area and to eliminate crossover component, resulting in a compact size and a low conductor loss. The two hybrids are designed at the top and bottom substrate with via-holes as the phase shifters and common ground plane at the centre. Phase shifters are designed using via-hole and Butler Matrix strip line is optimized for -45º, +135º, -135º and +45º output phase respectively. Consecutive phase input signal combiner/divider using the proposed Butler Matrix is executed at 28 GHz for fifth generation (5G) wireless connectivity.