US 4,638,190 AGranted

Digitally controlled wideband phase shifter

AssigneeGeneral Electric Company

InventorsYing C. Hwang, Young K. Chen, Louis J. Ragonese

Life of this patent

Estimating the term…

Loading patent…

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. The phase shifter is adapted to scaling at stepped angles, typically 111/4 or 221/2 degrees, is broadband and is applicable to frequencies ranging from a fraction of a gigahertz to many gigahertz.

Claims31

Dependent claims

A digitally controlled wideband phase shifter, which is adjustable in selected discrete angular steps, comprising

A. an input terminal for application of an AC input signal;
B. phase splitting means coupled to said input terminal for resolving said input signal into a first and a second vector component in mutual quadrature, and including a first and a second output terminal for supplying said first and second components respectively;
C. a first and a second dual gate MESFET, each MESFET having a source terminal, a drain terminal, a signal gate terminal and n-fold control terminals, and being subdivided into an n-fold plurality of selectively activated MESFET segments,
each segment having a predetermined width to achieve a desired transconductance, and including
(1) an electroded source region connected to said MESFET source terminal
(2) an electroded drain region connected to said MESFET drain terminal, and
(3) a gate region defined between said source and drain regions having
(i) a signal gate electrode disposed between said source and an activating gate electrode, electrically connected to said MESFET signal gate terminal for modifying the AC output signal current of said MESFET as a function of the segment transconductance, and
(ii) an activating gate electrode disposed between said signal gate electrode and said drain for turning current flow "ON" or "OFF" in said MESFET segment and electrically connected to one of said control terminals,
said first and second of said quadrature related vector components being applied to the signal gate terminals of said first and second MESFETS respectively,
said segments of said first MESFET being proportioned and ordered for connection to an electrical control signal coupled to the n-fold control terminals of said first MESFET such that successive combinations of active segments provide successive transfer values proportional to successive values of the sine function of an angle theta
said segments of said second MESFET being proportioned and ordered for connection to an electrical control signal coupled to the n-fold control terminals of said second MESFET such that successive combinations of activated segments provide successive transfer values proportional to successive values of the cosine function of said angle theta;
and
D. means for combining the quadrature related vector components at the outputs of said first and second MESFETS respectively proportioned to said sine and cosine values of said angle theta to form an output signal the phase of whose vector resultant represents a stepped rotation by said angle theta of the vector resultant of the input signal.

11 more elements

In a digitally controlled wideband phase shifter, which is adjustable in selected discrete angular steps, the combination comprising

A. a pair of input terminals for application of an AC input signal resolved into a first and a second vector component in mutual quadrature;
B. a first and a second dual gate MESFET, each MESFET having a source terminal, a drain terminal, a signal gate terminal and n-fold control terminals, and being subdivided into an n-fold plurality of selectively activated MESFET segments,
each segment having a predetermined width to achieve a desired transconductance, and including
(1) an electroded source region connected to said MESFET source terminal
(2) an electroded drain region connected to said MESFET drain terminal, and
(3) a gate region defined between said source and drain regions having
(i) a signal gate electrode disposed between said source and an activating gate electrode, electrically connected to said MESFET signal gate terminal for modifying the AC output signal current of said MESFET as a function of the segment transconductance, and
(ii) an activating gate electrode disposed between said signal gate electrode and said drain for turning current flow "ON" or "OFF" in said MESFET segment and electrically connected to one of said control terminals,
said first and second of said quadrature related vector components being applied to the signal gate terminals of said first and second MESFETS respectively,
said segments of said first MESFET being proportioned and ordered for connection to an electrical control signal coupled to the n-fold control terminals of said first MESFET such that successive combinations of active segments provide successive transfer values proportional to successive values of the sine function of an angle theta,
said segments of said second MESFET being proportioned and ordered for connection to an electrical control signal coupled to the n-fold control terminals of said second MESFET such that successive combinations of activated segments provide successive transfer values proportional to successive values of the cosine function of said angle theta;
and
C. means for combining the quadrature related vector components at the outputs of said first and second MESFETS to form an output signal, the phase angle of whose vector resultant represents a stepped rotation by said angle theta of the vector resultant of the input signal.

10 more elements

Dependencies are inferred from the claim text.