Tunable microstrip antenna using switchable patches

The latest and next generation mobile radio terminals require access to different wireless networks that operate on different radio frequency bands. Additionally requirements such as a varying asymmetric data rate are needed for the efficient transmission of multimedia services. To operate effectively such terminals need either a single ultra wideband antenna that spans all the useful mobile frequencies, or an antenna that can be tuned to the required relatively narrow bands when desirable. In this paper a low-profile tunable microstrip antenna structure using switched parasitic patches is studied. The frequency of operation of the prototype can be tuned from 1.36 GHz to 1.92 GHz using a total of 13 different switch combinations. The antenna is simulated, built and tested. The switches in the prototype are replaced with copper strip bridges. The measured results are in good agreement with the simulations.