An Adjustable Narrow Band Microwave Delay Equalizer

A simple low loss microwave delay equalizer for the delay equalization of narrow band microwave bandpass filters has been explored. This equalizer is quite small and does not require the use of additional components such as circulators or hybrids. It exhibits a reflection coefficient of less than 1 percent and possesses two very valuable and convenient features: a continuous adjustment of the delay shape and of the center frequency. The structure is analyzed theoretically, an equivalent circuit is derived, and expressions for both delay and loss are given. Also presented are design data and experimental results concerning the actual delay equalization of a bandpass filter and the temperature behavior of the equalizer and the filter-equalizer combination.