Excitation of TE11 Mode in Microwave Communication for Downhole While Drilling

In this paper, the excitation of the TE
l l
mode which is suitable in the downhole for gas drilling with high velocity gas flow is proposed. The proposed structure exploit two symmetrical loops which stretches from the aperture of the circular waveguide and connected to the inner wall of the waveguide. The simulation of the proposed excitation shows that the insertion loss is above −3.2 dB and the return loss is less than −15 dB from 2.4 GHz to 2.5 GHz. Then, the equivalent circuit of the excitation is established to explain the working mechanism. Good agreement of the S parameters is observed between the electromagnetic simulation and the circuit model. Finally, the comparison of the stress between the proposed structure and the probe is made using fluid-structure interaction analysis. The maximum stress of the proposed structure is 0.047 MPa while that of the probe is 0.31 MPa.