<p>Fabricated prototype: top and bottom views.</p>

The target bands at 2.4, 5.2, and 6.0 GHz yield a highest-to-lowest frequency ratio of 2.50, making compact integration of the low-band radiator particularly challenging. To address this issue, the 2.4-GHz driven patch is reactively loaded with narrow capacitive gaps, shorting vias, and meandered sections, reducing its resonant length from 33 to 13 mm (approximately 61%).

Two proximity-coupled parasitic patches generate the 5.2- and 6.0-GHz resonances. The spatially distinct current paths provide nearly independent control of the three operating bands. A prototype occupying 0.36 0.36 0.012, where is the free-space wavelength at 2.4 GHz, exhibits measured -dB impedance bandwidths of 20, 90, and 100 MHz and peak broadside realized gains of 3.1, 5.8, and 6.8 dBi, respectively.