Improved accuracies should be possible if transformers offering wider bandwidths such as multi-section quarter-wave transformers
are used, but employing these types of transformers would complicate the system since the analysis would have to include the effects of these various sections in de-embedding the S parameters of the samples.
The design uses two quarter-wave transformers
to match the split ports to the common port at the center frequency.
The leakage signal can be further reduced by using a number of chip capacitors and quarter-wave transformers
, as shown in Figure 10.
Cohn, "Microwave lens matching by simulated quarter-wave transformers
," IRE Transactions on Antennas and Propagation, vol.
(4,5) The power splitters used in the feed network consist of seven quarter-wave transformers
; consequently, it is not possible to obtain closed form solutions for the design.