A low cost method for testing integrated RF substrates

In this paper, a novel low-cost method for testing embedded passive filters in integrated radio frequency (RF) substrates is introduced. The introduced test method does not require external test stimulus and enables testing of these embedded RF passive circuits without vector network analyzer (VNA). The core principle of the proposed test method relies on including the passive filter through substrate surface probes into the feedback network of an external amplifier circuit located on the probe card, thereby causing the amplifier to oscillate. Failures in an embedded RF filter are detected by measuring changes in the oscillation frequency of the amplifier circuit. Hence, the test setup cost reduces. The introduced test method is demonstrated with both simulations and measurements. In addition, wafer-level testing of embedded RF passive circuits is also illustrated.