A Balanced Filtering Quasi-Yagi Antenna With Low Cross-Polarization Levels and High Common-Mode Suppression

Feng Wei,Xi-Bei Zhao,Xiao Wei Shi

doi:10.1109/access.2019.2931141

Abstract

A balanced planar quasi-Yagi antenna integrated with a bandpass filtering response is presented in this paper. The proposed balanced antenna consists of a balanced stepped-impedance microstrip-slotline transition structure, a driver dipole, a parasitic strip, and a bandpass filtering unit. A good differential-mode (DM) passband selectivity is formed by inserting a microstrip stub-loaded resonator (SLR) in the feed line of the quasi-Yagi antenna. This integration enables the antenna to achieve both compact size and high frequency selectivity. By controlling the dimensions of SLR, the central frequency and fractional bandwidth (FBW) can be easy to be adjusted. Meanwhile, the microstrip-slotline transition structure can achieve a good wideband common-mode (CM) suppression without affecting the DM ones, thus simplify the design procedure. The proposed antenna with low cross-polarization level and high CM rejection is found to be comparable to the conventional quasi-Yagi antenna. Furthermore, there are two radiation nulls on both sides of the passband to improve the selectivity effectively. In order to validate its practicability, the balanced antenna is designed and fabricated. The experimental results exhibit that the designed balanced filtering antenna features good filtering response, low cross-polarization level, and high CM rejection.

Highlights

In recent years, balanced circuits have attracted great attention and have been more and more utilized because of the high immunity to the environmental noise, interference and crosstalk between different elements, compared with the single ended counterparts
In order to build up fully balanced transceivers, balanced antennas and components are adopted for differential signals operation due to the direct integration with differential circuits
There is almost no CM signals which transfer into the driver dipole of the proposed antenna. It indicates that the CM radiation is effectively suppressed by introducing the balanced microstrip-slotline transition structure, while the DM radiation pattern remains stable in the passband

Summary

Introduction

In recent years, balanced circuits have attracted great attention and have been more and more utilized because of the high immunity to the environmental noise, interference and crosstalk between different elements, compared with the single ended counterparts. Microstrip to slotline transition structure are widely used in the design of balanced filters with intrinsic common-mode suppression. F. Wei et al.: Balanced Filtering Quasi-Yagi Antenna With Low Cross-Polarization Levels and High Common-Mode Suppression fed by two resonators was designed.

Results

Conclusion