Wide-band superconductive chirp filters

Chirp filters are described that consist of a miniature tapped superconductive stripline. The stripline consists of 40-μm-wide niobium thin films in a spiral pattern on 125-μm-thick silicon wafers, and tapping is effected by backward-wave couplers between neighboring lines. Sophisticated fabrication and packaging techniques have led to a now mature technology. Devices with 2.6-GHz bandwidths and time-bandwidth products of 98 are routinely fabricated that exhibit amplitude errors within a few tenths of a decibel and phase errors within a fraction of a degree of theoretical. In pulse-compression tests, matched amplitude-weighted devices yield peak relative side-lobe levels of -32 dB