Switchable slot antenna using close-coupled biasing technique

This paper presents a reconfigurable slot antenna that uses a close-coupled biasing technique to facilitate the switching between two frequency bands. The technique uses a very thin double layered flexible copper clad Mylar substrate with the slot antenna on the front side and the biasing circuits at the backside of the design. The biasing circuit uses a conventional PIN diode to switch between ON and OFF states. Each state corresponds to a separate operating band. The switching from one sub-band to another is done electronically by means of a BAR64 diode. In this first example, the two bands are located close to each other to increase the bandwidth of the antenna. The resulting -10dB bandwidth increases by 20% as compared with the OFF-state. The antenna has mostly omnidirectional radiation patterns at the two frequency bands. Simulation and measurement results are compared and discussed which are to be in good agreement with one another.