Thin Film Based Novel Impedance Matching Technique for Ka-Band Microstrip Antenna

A novel impedance matching technique is presented for slotted microstrip patch antenna (MPA) using thin-film structures to further enhance the matching at high frequencies. Three different types of thin-films using conducting, semiconducting and dielectric materials are deposited over the slot of a slotted rectangular MPA to investigate the impedance matching characteristics of the antenna. The materials considered include gold (Au) and silver (Ag) for conducting thin-films, zinc oxide (ZnO) and titanium dioxide (TiO
2
) for semiconducting thin-films and aluminium nitride (AlN) and silicon dioxide (SiO
2
) for dielectric thin-films. The proposed antenna is simulated in Ansys High Frequency Structural Simulator (HFSS) and the return losses (S11) of all the antennas with and without thin-film deposition are compared. It is found that the dielectric based thin-film using SiO
2
over the slot shows the minimum return loss of -39.10dB at 30.1 GHz with a film thickness of 250nm. This antenna shows a bandwidth of 0.95GHz and a gain of 7.51dBi. A linear relationship of all the materials with film thickness can be seen. Moreover, all the designed antennas are found to resonate within the 29GHz - 34GHz frequency band and hence the proposed MPA is best suited for Ka-band satellite applications.