Analysis of elliptical waveguides by the method of fundamental solutions

MMIC, with chip size of 1.5 1 mm. 4. MEASUREMENT The measurement is performed by putting the VCO MMIC chip into a test fixture, as shown in Figure 4. A test board is used to supply DC power to the chip and to output the oscillating signal through the SMA connector. There are two capacitors (100 pF and 10 F, respectively) connected in parallel to each DC supply line, which is used to bypass the undesired RF signals. The oscillating curve is displayed on an MS288C spectrum analyzer. The measurement results are shown in Figures 5 and 6. The operation condition for this VCO MMIC measurement is: Vd 3.0 V, Ids 18 mA. Figure 5 shows a typical oscillating signal with oscillating frequency of 25.0232 GHz, and Figure 6 shows the measured oscillating frequency and the associated output-power tuning curves. The designed VCO MMIC has a tuning range of 1.4 GHz at around 25.7 GHz with an output power of about 8 dBm. As mentioned above, the VCO MMIC was measured by inserting it into the test fixture shown in Figure 4. Clearly, the measured output power will be less than that released by the chip itself, due to the loss of output microstrip and the connector in the test ficture. On-wafer measurement result shows a loss of about 3 dBm for them; so, the output power released by the chip itself should be about 11 dBm. 5. CONCLUSION An active-biased 26-GHz VCO MMIC, based on a 0.25-m GaAS pHEMT process, has been presented in this paper. Its tuning range is 1.4 GHz with a central frequency of 25.7 GHz, and the output power is 11 1 dBm. The fabricated VCO MMIC chip size is 1.5 1.0 mm. ACKNOWLEDGMENTS