Analysis of Antenna Performance Degradation due to Coupled Electromagnetic Interference from Nearby Circuits

Hosang LEE
Kwangho KIM
Seongjin MUN
Chanseok HWANG
Wansoo NAH

IEICE TRANSACTIONS on Electronics   Vol.E103-C    No.3    pp.110-118
Publication Date: 2020/03/01
Publicized: 2019/08/27
Online ISSN: 1745-1353
DOI: 10.1587/transele.2019ECP5019
Type of Manuscript: PAPER
Category: Electromagnetic Theory
electromagnetic interference (EMI),  antenna performance degradation,  scattering parameters (S-parameters),  noise spectrum power,  active S-parameter,  

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This paper analyzes and compares two methods to estimate electromagnetically coupled noises introduced to an antenna due to the nearby circuits at a circuit design stage. One of them is to estimate the power spectrum, and the other one is to estimate the active S11 parameter at the victim antenna, respectively, and both of them use simulated standard S-parameters for the electromagnetic coupling in the circuit. They also need the assumed or measured excitation of noise sources. To confirm the validness of the two methods, an evaluation board consisting of an antenna and noise sources were designed and fabricated in which voltage controlled oscillator (VCO) chips are placed as noise sources. The generated electromagnetic noises are transferred to an antenna via loop-shaped transmission lines, degrading the performance of the antenna. In this paper, detailed analysis procedures are described using the evaluation board, and it is shown that the two methods are equivalent to each other in terms of the induced voltages in the antenna. Finally, a procedure to estimate antenna performance degradation at the design stage is summarized.