A Simple Compact Monopole Antenna With Variable Single- and Double-Filtering Function for UWB Applications

In this letter, a simple rectangular monopole antenna with variable band-notched function is proposed. The antenna is constructed on an FR4-epoxy substrate with thickness of 1.6 mm and ε
_r
= 4.4. The proposed antenna shows ultrawideband (UWB) characteristics from around 3 up to 10.6 GHz for . Two shorting pins running through the substrate connect the patch to the inverted L-shaped stubs printed on the bottom of the substrate to create multifiltering function. By changing the stubs' lengths, the proposed antenna shows variable single- and double-filtering characteristics.