Design and characterization of microstrip based E-field sensor for GSM and UMTS frequency bands

Abstract

An Electric (E-) field sensor based on coplanar waveguide-fed microstrip antenna to measure E-field strength for dual-band operation at 914 MHz and 2.1 GHz is proposed, designed, and characterized. The parametric optimization of the design has been performed to obtain resonance at global system for mobile communication and universal mobile telecommunication system frequency band. Low return loss (-17 dB and -19 dB), appropriate gain (0.50 dB and 1.55 dB), and isotropic behaviour (directivity ∼ 1 dB), respectively, at 914 MHz and 2.1 GHz, are obtained for probing application. Antenna factor (AF) is used as an important parameter to characterize the performance of the E-field sensor. The AF measurement is explained in detail and results are reported. Finally, using the designed E-field sensor, the E-field strength measurements are carried out in a transverse electromagnetic cell. The key sources of uncertainties in the measurement are identified, evaluated, and incorporated into the final results. The measurement results are compared with theoretical values, which are found in good agreement. For comparative validation, the results are evaluated with reference to an already calibrated commercially available isotropic probe.

Numerical Analysis and Measurement of Electric field Strength inside GTEM Cell at GSM Frequencies

“…A novel approach to suppress higher order modes at 914 MHz and 2.10 GHz is explained for the design of GTEM cell 5 . The performance of the probe is exhaustively characterised; details are Narang 7 . The matching condition and E-field strength inside the GTEM cell at different positions with varied input power is given and discussed.…”