Phase array antenna using a constant-gain phase shifter

An antenna array system comprising:

• a plurality of antennas, each antenna having an antenna port;
• a plurality of constant-gain phase-shifter circuits, each constant-gain phase-shifter circuit of the plurality of constant-gain phase-shifter circuits having an input connected to the antenna port of a corresponding antenna of the plurality of antennas, and an output;
• a summing circuit having inputs connected to corresponding outputs of each constant gain phase-shifter circuit and a summing circuit output to supply a summed signal that is a combination of all the summing circuit inputs;
• and
• wherein each constant-gain phase-shifter circuit further comprises:
• a first tank circuit comprising a first node to accept an input signal from an the corresponding antenna port, a first inductor connected between the first node and a reference voltage, and a first capacitor connected in parallel with the first inductor between the first node and the reference voltage, the first tank circuit modifying a phase and an insertion loss associated with the input signal;
• a variable gain circuit having a gain circuit input connected to the first node, a control input to accept a control signal, and a gain circuit output to supply a gain-modified signal;
• and
• a second tank circuit comprising a second node connected to the gain circuit output to supply a constant-gain phase-shifted signal to the corresponding input of summing circuit, a second inductor connected between the second node and the reference voltage, and a second capacitor connected in parallel with the second inductor between the first node and the reference voltage, the second tank circuit modifying the phase and insertion loss associated with the gain-modified signal.

A method for maintaining constant gain while phase-shifting a signal, the method comprising:

• accepting an input signal;
• modifying a modified input signal a first number of degrees, the modified input signal having a first insertion loss;
• amplifying the modified input signal to supply a gain-modified signal;
• and
• modifying the gain-modified signal a second number of degrees and with a second insertion loss to supply a constant-gain phase-shifted signal.