Active array antenna system

An active array antenna system comprising:

• a plurality of element antennas configured to receive carrier-wave frequency signals;
• and
• radio frequency circuits connected to the plural element antennas and comprising
• frequency converting circuits provided for each of said element antennas and configured to perform a frequency conversion between the carrier-wave frequency signals and intermediate-frequency signals by using local signals, and
• a variable phase shifter circuit provided for each of said element antennas and configured to shift phases of each of the local signals, the variable phase shifter circuit having a quadrature modulator.

An active array antenna system comprising:

• a plurality of transmission/reception element antennas configured to transmit/receive carrier-wave frequency signals;
• a reception radio frequency circuit supplied with received carrier-wave frequency signals from said transmission/reception element antennas;
• and
• a transmission radio frequency circuit configured to supply transmission carrier-wave frequency signals to said transmission/reception element antennas, wherein each of said transmission radio frequency circuit and said reception radio frequency circuit comprises:
• first frequency converting circuits provided for each of said transmission/reception element antennas and configured to perform a frequency conversion between the carrier-wave frequency signals and first intermediate-frequency signals by using first local signals,
• second frequency converting circuits provided for each of said transmission/reception element antennas and configured to perform a frequency conversion between the first intermediate-frequency signals and second intermediate-frequency signals by using second local signals, and
• a variable phase shifter circuit configured to shift phases of the second local signals.

An active array antenna system comprising:

• element antennas configured to receive carrier-wave frequency signals;
• and
• a radio frequency circuit connected to the element antennas and comprising
• frequency converting circuits provided for each of said element antennas and configured to perform a frequency conversion between the carrier-wave frequency signals and intermediate-frequency signals by using local signals, and
• a variable phase shifter circuit configured to shift phases of the local signals, wherein said variable phase shifter circuit comprises
• two bridge circuits configured to receive the local signals in the form of a differential signal and having two capacitors disposed on two opposite sides and two resistors disposed on other two opposite sides, resistance values of the capacitors and the resistors being different from one another, and
• a selector configured to selectively output either output of the two bridge circuits in response to a phase shift control signal.