A Compact Broadband Quadrature Coupler using 3D-Printing Package Technology

Compared to typical multilayer printed circuit board (PCB) process, 3D multimaterial printing technique has superior flexibility in the vertical axis with high accuracy. Multilayer package structure can be readily fabricated without preimpregnated (pp) layers, metal pads and etching process. Since, this article presents a broadband coupler with a quadrature phase using 3D printing technology to achieve a compact structure with an ultrathin profile. A compact broadband coupler (CBC) prototype with additional transmission lines attached to the mounting surface connections is involved for proof-of-concept. The proposed coupler covers the K and Ka bands simultaneously with a relative bandwidth of 53% and a compact size of 1.7 mm × 1.86 mm × 0.37 mm, taking advantage of the 3D-printed tight coupling lines in the vertical direction. Additionally, in broadband, the phase difference is restricted to 90±4° and the magnitude imbalance is -3.9±1.7 dB. These performances indicate that the proposed method is enforceable and viable for mm-wave package technology.