A PCB-compatible 3-dB coupler using microstrip-to-CPW via-hole transitions

• Published in: IEEE microwave and wireless components letters Vol. 16; no. 6; pp. 369 - 371
• Main Authors: CHIU, Jui-Chieh, LIN, Jih-Ming, HOUNG, Mau-Phon, WANG, Yeong-Her
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.06.2006; Institute of Electrical and Electronics Engineers
• Subjects: Applied sciences; Bonding; Circuit boards; Circuit properties; Coplanar waveguide (CPW); Coplanar waveguides; coupler; Coupling circuits; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Frequency measurement; Frequency ranges; Joining; Manufacturing processes; Microstrip; microstrip line; Microwave circuits, microwave integrated circuits, microwave transmission lines, submillimeter wave circuits; Microwaves; Multilayers; Nonhomogeneous media; Printed circuits; Waveguide transitions; Wire; Wires; Performance evaluation; Microwave coupler; Circuit design; Coplanar waveguide (CPW); Tapered waveguide section; coupler; Coplanar waveguides; Microstrip; microstrip line; Via hole
• ISSN: 1531-1309; 1558-1764
• DOI: 10.1109/LMWC.2006.875592

A 3-dB coupler by implementing microstrip-to-coplanar waveguide (CPW) via-hole transitions is proposed. The proposed coupler, with the advantages of wider coupled line widths and spacing without using any bonding wires, can eliminate the uncertain factors of conventional Lange couplers caused by the printed circuit board (PCB) manufacturing processes. The proposed coupler can be easily fabricated on a single-layer PCB substrate instead of using multilayer substrates. Good agreements between the simulation and the measurement in the frequency range from 0.45 to 5 GHz can be achieved. The measured results at the center frequency of 2.4 GHz have the return loss better than -15dB; the insertion loss of coupled and direct ports is about 3/spl plusmn/ 0.2dB and the relative phase difference of 89/spl plusmn/0.3/spl deg/. The dimension of the coupler is 3.1cm /spl times/ 1.8cm.