A simple filtering patch antenna based on stub‐loaded resonator

Abstract

In this article, a simple coaxial-feed filtering patch antenna based on stub-loaded resonator is investigated and analyzed. Owning to the addition of a pair of parasitic stubs, the original rectangular patch antenna acquires a new resonance point and an out-side radiation null beyond the upper band edge. Then, by establishing a transverse path (introducing connected stubs), the radiating and filtering responses at lower band have been enhanced accordingly. In short, it operates like a three-order filter with two-constrained radiation nulls along the passband outside. The novel design has been verified by machining and testing, which meets the expected lately. A fractional bandwidth of 28% and a stable realized gain of 5.8 dBi inband are finally measured, and more it also reaches a higher radiation efficiency of 83%. Besides, it exhibits a unidirectional radiation pattern with a low-cross polarization less than −20 dB in the boresight direction.

A slotline‐fed wideband dipole with filtering gain response

“…Besides, the third fusion design of filtering antennas adds parasitic elements in Ref. [12][13][14][15][16], which can avoid the extra insertion losses. Parasitic stub-loaded patches are adopted to provide two radiation nulls along the passband outside [12].…”

“…[12][13][14][15][16], which can avoid the extra insertion losses. Parasitic stub-loaded patches are adopted to provide two radiation nulls along the passband outside [12]. In Ref.…”

“…Although the designed antennas in Ref. [12][13][14][15][16] can achieve good filtering characteristics and two or more radiations nulls usually realised by different structures, those designs cannot change the locations of the radiation nulls simultaneously and keep the inband performance unchanged.…”