A Balanced Filtering Antenna With Ultrawideband Common-Mode Absorption

An ultrawideband common-mode (CM) absorption balanced feeding network using simple transmission line (TL) and electromagnetic (EM) wave coupling theory is proposed in this letter. The feeding network provides two channels for the propagation of EM waves, then CM signals are absorbed by the resistor through the CM channel, and differential-mode (DM) signals are transmitted in the DM channel by coupling. These two channels share part of the physical structure, but act relatively independently on EM waves. In addition, a filtering antenna with ultrawideband CM absorption is realized based on the feeding network. As demonstration, the prototype of the designed filtering antenna is fabricated and measured.