The test cost of RF systems is an increasing percentage of the overall system cost. This trend is mainly due to the traditional RF testing scheme based on measurement of specifications over a wide frequency range. A lower cost alternative is to use defect-based testing for RF circuits. However, the traditional defect models in the analog domain need to be revised to include high frequency effects in the RF domain. In this paper, we present a new defect model for breaks in metal traces to be used for defect-based testing in the RF domain. We present our fault model based on DC, AC, and noise characteristics and provide a case study for a transistor-level RF front-end. We confirm the AC characteristics of the model through EM simulations and compare our detectability results with the results of the resistive open-circuit model traditionally used in the analog test domain. Our study confirms that in many cases the resistive-based open-circuit model yields overly optimistic detectability results for defects in the signal path. We show that targeting particular defects and using their detectability information, the overall test time of RF devices can be reduced appreciably.