An electronic filter device comprises a high frequency section and a low frequency section. The high frequency section has an input coupling loop connected to an input connection of the filter device, and a gyromagnetic resonance element. The low frequency section comprises at least one inductor and at least one capacitor connected to the input coupling loop of the high frequency section. The two sections of the filter device have separate output connections.

An electronically tunable solid-state microwave frequency source comprises a transmission-absorption filter incorporated within a magnetic structure. The transmission-absorption filter is employed with a tunable solid-state oscillator and tunable solid-state multiplier to provide a continuously tunable microwave signal source with enhanced spurious signal attenuation over a multiple-octave tuning range. The filter structure comprises a sphere of monocrystalline garnet such as yttrium iron garnet (YIG) and two coupling loops disposed in the field region of an adjustable field DC magnet. The coupling loops are disposed orthogonal to the magnetic field and to each other. In a specific embodiment the first coupling loop is operative to receive at its input the fundamental frequency signal and at its output is grounded, and the second coupling loop is operative to receive a harmonic input signal at its input and to convey a desired output signal at its output. The magnetic sphere of the transmission-absorption filter typically shares the magnetic field of the YIG sphere used to produce the output of the tuned oscillator. The transmission-absorption filter is incorporated into a source including a switch, a fundamental frequency amplifier and a harmonic frequency amplifier.

A wide bandwidth frequency multiplier (48) multiplies a first frequency of an input signal (52) to generate an output signal (54) having a second frequency. The multiplier (48) includes first stage doubler (56). The doubler (56) includes a lumped element power splitter (62), a push-push amplifier (80), and a combining junction (96). The power splitter (62) splits the input signal (52) into first and second signals (70, 72) that are balanced in phase. A series resistive element (86) maintains amplitude balance between the first and second signals (70, 72). First and second feedback circuits (166, 184) are integrated with first and second transistors (164, 182) so that the push-push amplifier (80) operates over wide bandwidth. In addition, the multiplier (48) includes a second stage doubler (58) configured similar to the first stage doubler (56) for producing an output signal (54) that is quadruple the frequency of input signal (52). The first and second stage doublers (56, 58) are combined on a single integrated circuit.

The variation in the external bandwidth of input and output resonators of YIG filters and of single resonator device, is corrected by means of frequency selective impedance transformers. The transformers are comprised of specific impedance transmission lines which may be incorporated as integral parts of the YIG filter RF circuit.

The precision microwave/millimeter wave modulated signal source is a relatively low cost, compact, highly accurate and stable signal source covering the 2 to 40 Gigahertz frequency range. The pulse width and amplitude level of the output signal can be changed on every pulse in the signal pulse train. Pulse width range is 5 nanoseconds to 1 millisecond. Pulse repetition intervals can be changed between each pulse set with usable range from 10 nanoseconds to 100 milliseconds. Interval parameters can be adjusted with 1 nanosecond resolutions with stabilities of +/-200 picoseconds. The highly accurate and versatile selection of signal parameters, along with its compact size, makes this design useful as an embedded built in test signal source. This built in signal source can be used for verification of system performance for many electronic warfare systems.