Abstract: An apparatus and method provide an adjustable phase and time delay to an input signal. The apparatus includes an inverting element and first and second variable capacitors. The inverting element has a first end serially coupled with the input signal and a second end. The first variable capacitor is coupled between the first end of the inverting element and first voltage. The second variable capacitor is coupled between the second end of the inverting element and a second voltage. The first and second variable capacitors are separately adjustable to controllably vary a phase shift and a delay of a reflection of the input signal. The first and second voltages may be at the same or different potentials. The input signal may be coupled to the inverting element through a directional coupler, such as a circulator.

Abstract: A method and apparatus for implementing a delay line filter with a single cross-coupled pair of filter elements. In a first exemplary embodiment of the present invention, the filter is comprised of a plurality of symmetrically configured filter elements, wherein only two of the filter elements are cross-coupled. In a second exemplary embodiment of the present invention, the filter is comprised of a plurality of filter elements, wherein a first element is coupled to a second element, and the first and second elements are each coupled to at least two other elements and at least one of the at least two other elements for each of the first and second elements are the same.