Phase shifter, communication device, and phase shifting method
A phase shifter ( 60 ) is provided corresponding to an antenna element constituting an array antenna and is configured to change a phase of a radio frequency signal to be transmitted or received by a corresponding antenna element. The phase shifter ( 60 ) includes a first distributor ( 61 ) configured to distribute the radio frequency signal input thereto into a plurality of first distributed signals having mutually different phases; second distributors ( 62 ) provided corresponding to the first distributed signals, the second distributors each being configured to distribute a corresponding one of the first distributed signals into a plurality of second distributed signals having mutually different amplitudes; a controller ( 63 ) configured to control on/off of the second distributed signals; and a combiner ( 64 ) configured to combine the second distributed signals that are controlled on by the controller ( 63 ).
1. A communication device equipped with a beam steering function, the communication device comprising:
a transmission array antenna;
a plurality of first phase shifters provided corresponding to respective transmission antenna elements constituting the transmission array antenna, the plurality of first phase shifters each being configured to change a phase of a radio frequency signal to be transmitted by a corresponding transmission antenna element;
a reception array antenna; and
a plurality of second phase shifters provided corresponding to respective reception antenna elements constituting the reception array antenna, the plurality of second phase shifters each being configured to change a phase of a radio frequency signal received by a corresponding reception antenna element,
wherein the first and second phase shifters each include
a first distributor configured to distribute the radio frequency signal input thereto into a plurality of first distributed signals having mutually different phases,
second distributors provided corresponding to the first distributed signals, the second distributors each being configured to distribute a corresponding one of the first distributed signals into a plurality of second distributed signals having mutually different amplitudes,
a controller configured to control on/off of the second distributed signals, and
a combiner configured to combine the second distributed signals that are controlled on by the controller.
2. The communication device according to claim 1 , wherein the second distributors unequally distribute the respective first distributed signals into a plurality of second distributed signals having mutually different amplitudes.
3. The communication device according to claim 1 , wherein the combiner includes
first combiners provided corresponding to the second distributors, the first combiners each being configured to combine, of the second distributed signals distributed by a corresponding one of the second distributors, the second distributed signals that are controlled on by the controller, and
a second combiner configured to combine signals combined by the respective first combiners.
4. The communication device according to claim 3 , wherein the first combiners are each configured to combine the second distributed signals at a combining ratio that is equal to a distribution ratio of a corresponding one of the second distributors.
5. The communication device according to claim 1 , wherein
the first and second phase shifters each further include amplifiers provided in a stage following the second distributors and corresponding to the second distributed signals, the amplifiers each being configured to amplify a corresponding one of the second distributed signals, and
the controller is configured to control on/off of the second distributed signals by controlling on/off of power sources of the amplifiers.
6. The communication device according to claim 1 , wherein
the first and second phase shifters each further include switches provided in a stage following the second distributors and corresponding to the second distributed signals, and
the controller is configured to control on/off of the second distributed signals by controlling open/close of the switches.