An Ultra-wideband Differential Patch Antenna with Embedded Matching Sleeve shells

This paper reports the gain bandwidth expansion from 27.1% to 48.2% obtained with a new differential feeding structure featuring two sleeve shells and L-probes. Parametric studies on key structural dimensions are provided to reveal the bandwidth enhancing mechanism; the simulated results verify that adding the sleeve shell increases the impedance bandwidth from 35.3% to 88.8% for a single fed patch antenna with the same dimensions. In addition, applying the differential structure creates a symmetrical radiation pattern that directs its main lobe in the zenith direction (theta=0). The reshaped radiation pattern increases the average gain from 4.9 dBi to 8 dBi for the differential antenna in the impedance bandwidth from 3.27-5.52 GHz. Because of its high gain, ultra-wide bandwidth, low profile, and simple structure, the proposed antenna can be used in wideband wireless systems requiring high gain values.