Triple-Tuning Small Antennas for Increased Bandwidth [Antenna Designer's Notebook]

A method for designing a lossless network to triple tune an electrically small antenna is presented. This approach is based jointly upon Wheeler's definition of the reflection coefficients at the edges of the band, and upon Fano's criterion defining the maximum possible bandwidth. Examples are given for a small top-loaded antenna operated at two center frequencies, 175.5 MHz and 300 MHz, with values of Q equal to 100 and 19, respectively.