A compact two element quad-band printed quasi-Yagi antenna array loaded with inter-digital capacitor and LC resonator

In this paper, a two element array of printed quasi-Yagi antennas loaded with inter-digital capacitor (IDC) and LC resonator is presented for quad-band application. Use of IDC and LC resonator loading introduces additional lower order frequency bands, leading to quad-band characteristics as well as antenna miniaturization. Measurements carried on the fabricated prototype of the quasi-Yagi array shows impedance bandwidths of 3.33%, 4.54%, 4.50% and 8.97% at the center frequencies of 1.50 GHz, 2.21 GHz, 2.44 GHz and 2.92 GHz respectively. Directive end-fire radiation patterns are achieved at all operating bands of the proposed quasi-Yagi array. The overall size of array is 0.63λ0 × 0.49 λ0 where λ0 is the free space wavelength corresponding to the lowest resonance frequency of 1.50 GHz. The proposed quad-band antenna can be used in Wi- Fi / Bluetooth / WLAN / WiMAX as well as multiband RADAR applications.