Four port phase shifter

A circuit for phase shifting a signal within a predetermined frequency range by a predetermined amount comprising:

• a first port adapted for coupling to an input signal and coupled through a first, second and third impedance to a second port,
• said second port adapted for providing an output signal,
• a fourth impedance coupled between the junction of said first and second impedance and a third port,
• a fifth impedance coupled between the junction of said second and third impedances and a fourth port,
• said first, second and fourth impedances each have an impedance substantially different from one another,
• a first diode coupled to said third port,
• a second diode coupled to said fourth port, and
• means for biasing said first and second diodes to provide a sixth and seventh diode impedance respectively at first times and to provide an eighth and ninth diode impedance respectively at second times.

A circuit for phase shifting a signal within a predetermined frequency range by a predetermined amount comprising:

• a first port adapted for coupling to an input signal and coupled through a first impedance to a second port,
• said second port adapted for providing an output signal,
• said first port coupled through a second and third impedance respectively in series to a third port,
• said second port coupled through a fourth and fifth impedance respectively in series to a fourth port,
• a sixth impedance coupled between the junction of said second and third impedances and the junction of said fourth and fifth impedances,
• said first, second, third and sixth impedances each having an impedance substantially different from one another,
• a first diode coupled to said third port,
• a second diode coupled to said fourth port, and
• means for biasing said first and second diodes to provide a seventh and eighth diode impedance respectively at first times and to provide a ninth and tenth diode impedance respectively at second times.

A circuit for phase shifting a signal within a predetermined frequency range by predetermined amounts in response to a plurality of control signals comprising a plurality of phase shifters coupled in series, each phase shifter providing a predetermined phase shift comprising a first port adapted for coupling to an input signal and coupled through a first impedance to a second port, said second port adapted for providing an output signal, said first port coupled through a second, third and fourth impedance respectively in series to a third port, said second port coupled through a fifth, sixth and seventh impedance respectively in series to a fourth port, an eighth impedance coupled between the junction of said second and third impedances and the junction of said fifth and sixth impedances, a ninth impedance coupled between the junction of said third and fourth impedances and the junction of said six and seventh impedances, said first, second, third, fourth, eighth and ninth impedances each having an impedance substantially different from one another, a first diode coupled to said third port, a second diode coupled to said fourth port, and means for biasing said first and second diodes to provide a tenth and eleventh diode impedance respectively at first times and to provide a twelfth and thirteenth diode impedance respectively at second times, said means for biasing coupled to a respective one of said plurality of control signals.