Two configurations for an active microwave delay line with feedback to improve the loss per unit delay time have been made and characterized. The lines utilized thin yttrium iron garnet (YIG) film, magnetostatic wave (MSW) passive elements, a microwave amplifier, and a variable attenuator connected in a feedback loop. The two delay line setups used a surface wave (MSSW) configuration with a single MG element and a nondispersive configuration with MSSW and backward volume wave (MSBVW) delay lines in series. For each setup, a sequence of delayed pulses at the output is observed when a single microwave pulse is fed to the input. The one-pass delay time T of the pulse through the MSW delay line and the number n of circulations in the feedback loop defines the total delay time nT for the nth pulse. The feedback resulted in a reduction in the output pulse decay rate and longer useful delay times. For a passive delay line with no feedback, typical values of the loss p.u. delay time L and useful delay time (nT)/sub U/ were -110 dB//spl mu/s and 0.1-0.2 /spl mu/s, respectively. With feedback for the MSSW delay line, a 4.5-GHz operating frequency, and 40 ns input pulses, L and (nT)/sub U/ were -19 dB//spl mu/s and 0.6 /spl mu/s, respectively. Feedback with the nondispersive delay line gave L and (nT)/sub U/ values of -12 dB//spl mu/s and 3 /spl mu/S, respectively, for 4.5-GHz, 40-ns input pulses.
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机译：有源微波延迟线的两种配置具有反馈，可以改善每单位延迟时间的损耗，并进行了表征。这些生产线利用了钇铁石榴石（YIG）薄膜，静磁波（MSW）无源元件，微波放大器以及连接在反馈回路中的可变衰减器。这两个延迟线设置使用具有单个MG元件的表面波（MSSW）配置以及具有MSSW和反向体积波（MSBVW）延迟线串联的非分散配置。对于每种设置，当将单个微波脉冲馈入输入时，会观察到输出处的一系列延迟脉冲。通过MSW延迟线的脉冲的单次延迟时间T和反馈回路中循环数n定义了第n个脉冲的总延迟时间nT。反馈导致输出脉冲衰减率的降低和更长的有用延迟时间。对于无反馈的无源延迟线，损耗p.u的典型值为。延迟时间L和有用延迟时间（nT）/ sub U /分别为-110 dB // spl mu / s和0.1-0.2 / spl mu / s。通过MSSW延迟线的反馈，一个4.5 GHz的工作频率和40 ns的输入脉冲L和（nT）/ sub U /分别为-19 dB // spl mu / s和0.6 / spl mu / s。对于4.5 GHz，40 ns输入脉冲，使用非分散延迟线的反馈分别得出L和（nT）/ sub U /值分别为-12 dB // spl mu / s和3 / spl mu / S。
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