Low-frequency test method for integrated RF substrates

This paper presents a low-frequency test method for testing integrated RF substrates with embedded RF passive filters. The proposed method enables testing of embedded high-frequency (GHz) passive filters at low frequencies (of the order of a few MHz). This method allows the testing of embedded RF filters without applying any external test stimulus to them (test stimulus is generated by the probe card). Also, at production-test floor, the proposed method does not require a vector network analyzer (VNA). In addition, the method enables the prediction of RF (GHz) specifications from the low-frequency (MHz) signal. As compared to a conventional test method that uses VNA, the proposed method reduces the test-setup cost by around 75%. The proposed test method is demonstrated with both simulations and measurements. Also, the method has been demonstrated at wafer level for testing commercially available 1.45-GHz embedded RF filters at 60 MHz.