Improved-Sensitivity Resonant Electric-Field Probes Based on Planar Spiral Stripline and Rectangular Plate Structure


The designs of two resonant electric-field probes with improved sensitivity for near-field measurements are proposed and measurements in weak radiated level are conducted. One probe is the resonant monopole probe and the other is named the resonant T-shaped probe with further improved sensitivity. Each of the two probes is fabricated on four-layer printed circuit board using high-performance and low-loss Rogers material (εr = 3.48 and tanδ = 0.0037), which consists of an LC resonator made up of a planar spiral stripline (inductor) and a rectangular plate (capacitor), a single-stub transformer, and a SubMiniature version A connector. The LC resonator can achieve a specific resonant frequency for a specific narrowband of interest with the pure input resistance. The single-stub transformer is used to transform the pure input resistance to the input impedance of measurement instruments to acquire maximum transmission power. Compared with the referenced broadband probe with the same physical size of tip, the measured |S12| of the resonant monopole probe is enhanced by 9 dB at the resonant frequency. The resonant T-shaped probe proposed has 3.3-dB sensitivity higher than the resonant monopole probe in terms of |S12|. In order to validate the improved sensitivity of the resonant probes, comparisons on the improvement of sensitivity with other probes are also introduced.


Electrical and Computer Engineering

Research Center/Lab(s)

Electromagnetic Compatibility (EMC) Laboratory


National Natural Science Foundation (China)
Defense Industrial Technology Development Program (China)


This work was supported in part by the National Natural Science Foundation of China (NSFC) under Grant 61427803 and Grant 61271044 and in part by the Defense Industrial Technology Development Program under Grant JCKY2016601B005.

Keywords and Phrases

Crystal resonators; Electric fields; Electromagnetic pulse; Natural frequencies; Plates (structural components); Printed circuit boards; Resonators; Signal interference; Strip telecommunication lines; High sensitivity; Input resistance; Measurement instruments; Near-field measurements; Rectangular plates; Resonant; Resonant probes; Transmission power; Probes; Electric-field probe; Electromagnetic interference (EMI); High sensitivity

International Standard Serial Number (ISSN)

0018-9456; 1557-9662

Document Type

Article - Journal

Document Version


File Type





© 2018 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

01 Mar 2019