Enhancement of mechanical resonant modes by miniaturization of frequency tunable MEMS-enabled microstrip patch antenna

Any mechanically suspended structure is subject to unwelcomed environmentally induced mechanical vibrations. The designer needs to use a design strategy in order to those interferences don’t disturb the normal operation of the structure by producing undesirable outputs. This paper proposes a new method for enhancing mechanical resonant frequencies of MEMS-based frequency reconfigurable microstrip patch antenna. The objective of enhancing mechanical resonant frequencies is to make the antenna structure resistant against environmentally induced mechanical disturbances. The novelty of this design is in creating embedded slots on antenna patch and membrane for decreasing the mass of the suspended part of the antenna. The mass reduction achieved in the proposed antenna can be viewed from two perspectives; (1) by etching out embedded slots on patch and membrane the mass of the suspended structure decreases (2) creating embedded slots on antenna patch considerably decreases the operating frequency, hence it is not need to increase patch dimensions in order to operate in low operating frequencies. In order to show the effectiveness of proposed method, four antennas with operating frequencies of 15, 10, 5 and 1 GHz are designed. The first mechanical resonant frequency of the antennas designed by proposed method are 1,234, 959, 521 and 97 Hz, respectively. However, the antennas designed by conventional method have the first mechanical resonant frequency of 620, 306, 100 and 2 Hz. Comparing these results, it can be obviously seen that by the use of proposed method the mechanical resonant frequency of the antenna is considerably enhanced.