Abstract: A novel signal scaling MESFET of a segmented dual gate design is disclosed. The MESFET, which is monolithically integrated on a semi-insulating substrate capable of localized surface modification to form active semiconductor regions using MMIC (monolithic microwave integrated circuit) techniques, has a small AC signal transfer which is adjustable in selected discrete steps. For operation in the gigahertz range, the substrate is preferably of gallium arsenide.In applying the MMIC technique, the MESFET, including segment electrodes and segment interconnections, and the electrical connections, signal paths, and passive components connected to the MESFET are formed on the substrate and defined by a photolithographic process. The technique permits reproducable feature definition and very compact minimum reactance segment interconnections, reducing deleterious parasitics and facilitating virtual unitary MESFET operation to very high frequencies.

Abstract: A digitally controlled wideband phase shifter is disclosed in which an input signal is resolved into two quadrature related components, the components are scaled in a stepped digital manner in proportion to the sine and cosine of the phase shifting angle, and then recombined to reconstitute a phase shifted replica of the input signal. The scalers are segmented MESFETS of a dual gate design in which each segment, has a predetermined transconductance and may be gated "ON" or "OFF" by a control signal to affect the overall transconductance of the scaler, and thereby the scaling factor.The phase shifter is implemented by a monolithic microwave integrated circuit technique in which the preferred substrate material is gallium arsenide, and in which all active device and circuit features are formed on the substrate by a photolithographic process.

Abstract: A sensitive and precise detector is described for application in determining the "Centroid" of the video pulse of a radar return echo. A tunnel diode, connected and biased in a balanced configuration with respect to ground and selected taps on a signal delay line, is the key element of the circuit. The sum and/or difference of the tapped signals are formed in such a manner that a precise zero crossing, corresponding to the "centroid" of the pulse, may be determined. The special characteristics of the tunnel diode are utilized to achieve additional objects, base line noise immunity, multiple echo self resetting, and high speed-precision response. The tunnel diode is positioned in relation to four (or more) input signals and ground such that with no signal on the delay line, it is biased - at a stable low-current-high-voltage state.