Processing, Fabrication, and Demonstration of HTS Integrated Microwave Circuits
Abstract
Further measurements of nonlinear distortion in HTS filters were made during this reporting period. Third-order spurious intermodulation products were measured at 77K for one of the channels (center frequency near 4 GHz) in the filter bank made recently for the Navy HTSSE-II program. This was done to determine if the improved quality of our films will reduce the distortion in devices. The results are shown in Figure 1, where the measurements are plotted on the same graph as those for the X-band filter at 77K, included in last quarter's report. Fewer points were taken, and over a narrower range of input power levels than was the case for the X-band filter in order to utilize only the maximum sensitivity of the spectrum analyzer and minimize its contribution to the intermodulation distortion measured. Similar measurements made recently on the X-band filter agreed with those previously taken. As can be seen from Figure 1, the data taken in this fashion follow a 3:1 slope, giving a third-order intercept point of 35 dBm for the newer, 4 GHz filter compared with 20 dBm for the older, X-band filter. Assuming that the nonlinear behavior is independent of frequency, we attribute the lower third-order spur level of the newer filter to the higher quality of the YBCo films grown now compared to those grown in 1990, when the X-band filter was made. Table I compares the growth techniques used then with those currently used. The most significant feature of the new films is the elimination of the CuO particulates on the film surface. Earlier films, from which the X-band filters were made, had a high density of CuO "boulders" while those grown today are quite smooth and featureless.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 25, 1993
- Accession Number
- ADA269331
Entities
People
- G. R. Wagner