A Wide Stopband Balun Bandpass Filter with Its Application to Balanced Quasi-Yagi Antenna

作者：Zhang, Gang; Qian, Zhenyao; Chen, Yushou^*; Zhao, Yang

来源：Wireless Communications and Mobile Computing, 2018, 2018: 4725072.

DOI：10.1155/2018/4725072

• DESIGN

A new microstrip balun bandpass filter (BPF) with wide stopband is presented. It is realized by utilizing the out-of-phase feature of standing-wave distribution on a half-wavelength (lambda/2) open-ended microstrip line and the resonant characteristics of the triple-mode resonators. For demonstration, a prototype balun BPF operating at central frequency (f(0)) of 2.34 GHz with fractional bandwidth (FBW) of about 16.7% is designed. The presented balun BPF not only exhibits nice balanced response with 0.47 dB magnitude imbalance and 4.3 degrees phase difference but also achieves 30-dB harmonic suppression up to 6.40 GHz (2.7 f(0)). Afterward, this presented design is embedded into a balanced quasi-Yagi antenna to obtain high-selective radiation and wide stopband rejection. Experimental results of the implemented antenna indicate less than 10 dB reflection coefficient, 4.49-5.38 dBi gain, and 12.71-19.62 dB front-to-back ratio within the operating bandwidth.

• 出版日期2018
• 单位南京师范大学