Abstract: A temperature compensated time delay element employs a non-temperature compensated delay element along a first delayed path, and a second non-temperature compensated delay element along a second "undelayed" path to provide a net time delay equal to the difference between the delays in the delayed and undelayed paths. The substrate materials used in the delay elements in the delayed and undelayed paths, and the time delays of the two paths, are selected such that the variation of net phase shift, or time delay, with temperature is zero. The temperature coefficients of the substrate materials in the delayed and undelayed paths can both be positive, thus allowing the use of common substrate materials. The temperature compensated time delay element finds particular utility in differentially coherent signal detection systems.

Abstract: Periodic fins are provided on the lid of a microwave integrated circuit (MIC) package in order to reactively suppress specified bands of frequency and thereby increase the permissible dimensions of the MIC package.