| abstract |
A compact, efficient and electronically tunable antenna is presented. A single-fed resonantnslot loaded with a series of PIN diode switches constitute the fundamental structurenof the antenna. The antenna tuning is realized by changing its effective electricalnlength, which is controlled by the bias voltages of the solid state shunt switchesnalong the slot antenna. Although the design is based on a resonant configuration,nan effective bandwidth of 1.7:1 is obtained through this tuning without requiringna reconfigurable matching network. Four resonant frequencies from 540 to 890nMHz are selected in this bandwidth and very good matching is achieved for all resonantnfrequencies. Theoretical and experimental behavior of the antenna parametersnis presented and it is demonstrated that the radiation pattern, efficiency andnpolarization state of the antenna remain essentially unaffected by the frequencyntuning. |