Table of Contents
International Journal of Microwave Science and Technology
Volume 2013, Article ID 892590, 4 pages
Research Article

A Parallel-Strip Balun for Wideband Frequency Doubler

Department of Electronic Engineering, City University of Hong Kong, Hong Kong

Received 18 September 2013; Revised 2 November 2013; Accepted 9 November 2013

Academic Editor: Yong Xin Guo

Copyright © 2013 Leung Chiu and Quan Xue. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A parallel-strip phase inverter with a pair of simple impedance matching networks is designed. The phase inverter introduces the almost frequency independent 180° phase shift and was employed in the wideband parallel-strip balun. The balun was designed and measured with the maximum magnitude imbalance of 0.5 dB and the maximum phase imbalance of 6.0°. The proposed balun is used as input network for the wideband balanced frequency doubler. The proposed frequency doubler achieves significant conversion gain from 0.1 GHz to 1.7 GHz. The frequency doubler achieves 7.4 dB conversion gain and 23 dB fundamental signal suppression at 1 GHz.