MATCHING NETWORK USING ONE CONTROL ELEMENT FOR WIDELY TUNABLE ANTENNAS

A tunable impedance matching network is applied to achieve very widely tunable antennas, whose geometries are indepen- dent and unchanged to simplify the design. The attached matching network as the antenna feeding network enables any unspecifled UWB antenna to tune the operation frequency continuously with high se- lectivity by merely one single control. This is quite difierent from fllter-based concept which is complicated to co-design and implement a tiny narrow band tunable fllter over wide frequency ranges and very di-cult to control with one element. And also the design, adjustment, and optimization of the matching network are much simpler, quicker, and lower cost than geometry-modifled antenna design. The analysis of precise high frequency circuit models is used predict the perfor- mance in simulation. Fabricated prototype antennas are measured by using horn antennas to validate the antenna performance. The tun- able frequency ranges from 1.8GHz to 2.8GHz (155%) and 2.19GHz to 3.86GHz (176%). Moreover, compared to other matching network- based solutions, non-ideal efiects in undesired bands other than the operation frequency band are suppressed, so the performance is im- proved. One wide-tuning antenna using one single element to control can be carried out by tunable matching networks without complicated designs.