Abstract
In this paper, an approximate resonance model of frequency agile quasi-lumped resonator antenna operates in the band 802.11ac is presented. The proposed quasi-lumped antenna formed of straight-line inductor parallel with the interdigital capacitor. The radiating quasi-lumped dimensions were calculated at 5.8 GHz frequency. Then, the antenna prototype simulated the by CST Microwave Studio. The antenna equivalent resonance model lumped elements were extracted based on antenna calculated dimensions. The Agilent ADS used to simulate the antenna equivalent resonance model. Once the resonance frequency is adjusted, two varactor diodes equivalent circuit connected to the quasi-lumped resonator for tuning the resonance frequency. The CST prototyped antenna shows a significant size reduction of 5.6 x 5.8 mm with operating frequency of 5.8 GHz. The antenna ADS equivalent model resonance frequency is 5.8 GHz. Whilst, the operating frequency of antenna model employing the loading varactor diodes ranges from 5.18 GHz to 5.825 GHz which is the operation band of 802.11ac.