Low-Cost Broadband Electronic Coupler for Estimation of Radiated Emission of Integrated Circuits in TEM Cell

Abstract : TEM cell is a well-known method for the qualification of radiated electromagnetic emission from integrated circuits. Combined with a 180° hybrid coupler, it provides a simple method for quantifying radiated emission. However, typical transformer or coupled line-based hybrid couplers have limited bandwidth which cannot cover the full frequency range required by integrated circuit emission tests (150 kHz to 1 GHz). This paper presents the design and the validation of a low-cost broadband electronic version of a 180° hybrid coupler dedicated to the estimation of radiation emission from TEM cell measurements. The proposed prototype is able to cover a large frequency range (from DC to 1 GHz) with a sufficient sensitivity and dynamic range for radiated emission tests in TEM cell. The cost of the presented coupler is very reasonable as it is entirely based on commercial op-amps.