Optimized Ultrawideband and Uniplanar Minkowski Fractal Branch Line Coupler

Mohammad Jahanbakht,Mohammad Tondro Aghmyoni

doi:10.1155/2012/695190

Abstract

The non-Euclidean Minkowski fractal geometry is used in design, optimization, and fabrication of an ultrawideband (UWB) branch line coupler. Self-similarities of the fractal geometries make them act like an infinite length in a finite area. This property creates a smaller design with broader bandwidth. The designed 3 dB microstrip coupler has a single layer and uniplanar platform with quite easy fabrication process. This optimized 180° coupler also shows a perfect isolation and insertion loss over the UWB frequency range of 3.1–10.6 GHz.

Highlights

Ultrawideband technology has been used in many branches of science and wide range of applications such as radars, navigation, telemetry, mobile satellite communications, biomedical systems, the direct broadcast systems, and remote sensing utilities
Microstrip power divider and coupler designs and topologies which achieved compact size and broadband operation of the component could be categorized in some major methods including (a) wideband stub matching, (b) multistaging of the ordinary components, (c) multilayer and multiwafer packaging technologies, (d) deforming the shapes and using alternative geometries
As an instance of the first category, a 3 dB power divider on microstrip line is analyzed and designed in [1] using UWB stub matching technique. This divider is formed by installing a pair of stepped-impedance, open-circuited stubs, and parallel-coupled lines to two symmetrical output ports

Summary

Introduction

Ultrawideband technology has been used in many branches of science and wide range of applications such as radars, navigation, telemetry, mobile satellite communications, biomedical systems, the direct broadcast systems, and remote sensing utilities. As an instance of the first category, a 3 dB power divider on microstrip line is analyzed and designed in [1] using UWB stub matching technique. This divider is formed by installing a pair of stepped-impedance, open-circuited stubs, and parallel-coupled lines to two symmetrical output ports. In this class, an UWB microstrip power divider with good isolation and sharp roll-off skirt is proposed in [2].

Coupler Design and Theory

Results and Discussion

Conclusion