Compact Pixelated Microstrip Forward Broadside Coupler Using Binary Particle Swarm Optimization
Kourosh Parsaei, Rasool Keshavarz, Rashid Mirzavand, Negin Shariati
Abstract
In this paper, a compact microstrip forward broadside coupler (MFBC) with high coupling level is proposed in the frequency band of 3.5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim $ </tex-math></inline-formula> 3.8 GHz. The coupler is composed of two parallel pixelated transmission lines. To validate the design strategy, the proposed MFBC is fabricated and measured. The measured results demonstrate a forward coupler with 3 dB coupling, and a compact size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.12\,\,\lambda \text{g}\,\,\times 0.10\lambda \text{g}$ </tex-math></inline-formula> . Binary Particle Swarm Optimization (BPSO) design methodology and flexibility of pixelation enable us to optimize the proposed MFBC with desired coupling level and operating frequency within a fixed dimension. Also, low sensitivity to misalignment between two coupled TLs makes the proposed coupler a good candidate for near-field Wireless Power Transfer (WPT) application and sensors.