Antenna Decoupling Based on Self-Resonance Frequencies of Common Mode and Differential Mode

Abstract

This article presents a simple and effective decoupling approach based on the common mode (CM) and differential mode (DM) analysis to solve decoupling problem between two symmetrical antenna elements. Especially, the concept of the self-resonance frequencies of CM and DM is utilized in antenna decoupling analysis. It is found that when the self-resonance frequencies of CM and DM are the same, strong mutual coupling between two symmetrically and closely placed two-port antennas can be completely eliminated. The difference between self-resonance frequency and resonance frequency is discussed; and the method of obtaining the self-resonance frequencies of CM and DM is given. Since the proposed antenna decoupling judgment condition is straightforward and simple, it can effectively deal with any kind of closely placed antenna system with a plane of symmetry; and obtain good decoupling effect simply and easily. The effectiveness, feasibility and advantage of the proposed decoupling condition for the CM and DM analysis are demonstrated through several symmetrical two-port antenna examples. The decoupling approach proposed in this article can undoubtedly make the common mode and differential mode analysis for solving antenna decoupling problems more effective and practical.

Keywords

• Antenna decoupling
• common and differential modes analysis
• coupled resonator
• equivalent circuit of antenna system
• self-resonance frequency