A miniaturized millimeter‐wave branch‐line coupler using nonsymmetrical T‐shape structure with quasi‐stepped impedance resonator

Abstract

In this study, a novel ka‐band compact‐size branch‐line coupler was proposed. The coupler was designed and fabricated with WIN Semiconductors 0.15‐μm pseudomorphic high electron‐mobility transistor process. The design method, simulation data, and measurement results of the proposed coupler were also discussed. The coupler occupied less than 45% of the circuit area compared with conventional design at 30 GHz, and did not implement any lumped elements via‐hole grounding, and bonds wire, making it simpler to design, easier to fabricate, and lower cost. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2950–2953, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22941

Highly miniaturized wideband 3‐dB branch‐line hybrid with second harmonic‐suppression

“…The traditional single‐section BLH composed of four 90° microstrip‐lines (MLs) exhibits narrow‐bandwidth, occupies large circuit‐area, and generate harmonics. Several miniaturization techniques have been developed to reduce the size of the single‐section BLH . The overall size of the single‐section branch‐line coupler has been reduced by employing an asymmetric T‐shaped model .…”

Slow-wave resonant structures in branch-line coupler miniaturization: A case study

“…An adequate modification of a signal line in the form of a T-shaped topology [1] as well as a -shaped geometry [2][3][4][5][6] has proven to be a valuable method of branch-line coupler miniaturization (55% in [1], and 23-61% in [2][3][4][5][6]). Subsequently, several improvements have been proposed to aforementioned techniques by exploitation of singular or multiple stubs constructed from high-and lowimpedance segments [7][8], folded strips [9][10][11][12][13], steppedimpedance resonators [14][15] or other building blocks [16] resulting in 71-71%, 61-74%, 55-78%, and 37% scale of miniaturization, respectively. Although a significant degree of minimization has been achieved in numerous cases, the interior of the coupler has rarely been accommodated in a highly efficient manner.…”

Design considerations for compact microstrip resonant cells dedicated to efficient branch‐line miniaturization

“…A conventional branch‐line coupler offers a simple planar topology composed of four quarter‐wavelength transmission line segments easily realizable in a standard PCB fabrication process; however, the consumption of a large surface area, especially at the low operating frequency, becomes a major drawback that must be taken into account. This problem has been addressed throughout the years in several ways [1–30].…”

“…Another viable concept of branch‐line coupler miniaturization based on the implementation of various discontinuities along the microstrip transmission line has been extensively reported [7–30]. The modification of a signal line in the form of T‐shaped geometry [7] as well as π‐shaped topology [8–12] has proven to be useful in the process of branch‐line coupler size reduction (55% in Ref.…”

“…[8–12]). Subsequently, several improvements have been proposed to aforementioned techniques by utilization of singular or multiple stubs constructed from high‐ and low‐impedance segments [13, 14], folded strips [15–19], stepped‐impedance resonators [20, 21], or other building blocks [22] resulting in 71–72%, 61–74%, 55–78%, and 37% scale of miniaturization, respectively. Although a significant degree of minimization has been achieved in numerous cases, the interior of the coupler has seldom been accommodated in a highly efficient manner.…”