Frequency translation of true time delay signals

A method for controlling the beam pointing direction of phased array radars comprising the steps of:

• generating a first signal of a first signal frequency true time delaying said first signal by applying a true time delay T thereto;
• generating a local oscillator signal of a local oscillator frequency .omega..sub.2 ;
• delaying said local oscillator signal by a predetermined amount to provide a delayed local oscillator signal, including modulo 2.pi. phase shifting said local oscillator signal by a phase shift equivalent to the modulo 2.pi. value of said true time delay applied to said first signal;
• mixing said true time delayed first signal and said delayed local oscillator signal such that a sum of said first signal and said delayed local oscillator signal forms a transmit signal with a phase which is only a function of (.omega..sub.1 +.omega..sub.2);
• and
• sending said transmit signal to an antenna element for transmission.

A method for steering phased array radar antenna comprising a plurality of discrete antenna elements comprising the steps of:

• generating a first signal of a first signal frequency .omega..sub.1 ;
• delaying said first signal independently for each of the plurality of discrete antenna elements by applying a true time delay T thereto to form a plurality of true time delay beamsteering signals, one for each of the plurality of antenna elements, having a particular delay associated with each of the plurality of antenna elements which is determined by the direction of transmission desired;
• generating a local oscillator signal of a local oscillator signal .omega..sub.2 ;
• delaying said local oscillator signal independently for each of the plurality of discrete antenna elements by an amount based on a desired direction of antenna transmission to form a plurality of delayed local oscillator signals, including true time delaying said local oscillator signal by an amount equivalent to said true time delay applied to each of said true time delay beamsteering signals.

A method for steering phase array radar antenna comprising a plurality of discrete antenna elements comprising the steps of:

• generating a first signal of a first signal frequency .omega..sub.1 ;
• delaying said first signal independently for each of the plurality of discrete antenna elements by applying a true time delay T thereto to form a plurality of true time delay beamsteering signals, one for each of the plurality of antenna elements, having a particular delay associated with each of the plurality of antenna elements which is determined by the direction of transmission desired;
• generating a local oscillator signal of a local oscillator signal .omega..sub.2 ;
• delaying said local oscillator signal independently for each of the plurality of discrete antenna elements by am amount based on a desired direction of antenna transmission to form a plurality of delayed local oscillator signals, including modulo 2.pi. phase shifting said local oscillator signal by a phase shift equivalent to the modulo 2.pi. value of said true time delay applied to each of said true time delay beamsteering signals;
• mixing said plurality of true time delay beamsteering signals with said plurality of delayed local oscillator signals for each of said plurality of antenna elements such that a sum of said true time delay beamsteering signals and said delayed local oscillator signals form a plurality of transmit signals with phases which are only a function of .omega..sub.1 +.omega..sub.2), one for each of said plurality of antenna elements;
• and
• sending each of said plurality of transmit signals to an associated antenna element for transmission.