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Multiple Harmonic Self Steering Phased Array

IP.com Disclosure Number: IPCOM000091466D
Original Publication Date: 1968-Feb-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 3 page(s) / 70K

Publishing Venue

IBM

Related People

Muehldorf, EI: AUTHOR

Abstract

This method of connection allows using essentially one single amplifier for all connections between pairs of receiving and corresponding transmitting elements of a retrodirective phased array. Shown on the left side are receiving elements 1...n and the corresponding transmitting elements 1'...n' of a linear retrodirective array. The receiving elements as well as the transmitting elements are equidistantly arranged. Then element 1 receives the signal of frequency f with a phase angle of zero degrees indicated by f/O , element 2 receives the signal of frequency f with a phase angle psi indicated by f/psi, etc.

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Multiple Harmonic Self Steering Phased Array

This method of connection allows using essentially one single amplifier for all connections between pairs of receiving and corresponding transmitting elements of a retrodirective phased array. Shown on the left side are receiving elements 1...n and the corresponding transmitting elements 1'...n' of a linear retrodirective array. The receiving elements as well as the transmitting elements are equidistantly arranged. Then element 1 receives the signal of frequency f with a phase angle of zero degrees indicated by f/O , element 2 receives the signal of frequency f with a phase angle psi indicated by f/psi, etc.

Local oscillator LO(1) produces a signal at frequency f(1) which is used for converting the signal to an intermediate frequency.

Harmonic generator H(1) used to generate n-2 harmonics of the oscillator. All harmonics have a phase angle of zero degrees with respect to the oscillator signal. They are shown as 2f(1)/O , 3f(1)/O, etc. The signals received by elements 1 and 2 are converted by the local oscillator signal, frequency f(1) with phase angle of zero degrees, and by the first harmonic of the oscillator, frequency 2f(1) with zero degree phase respectively. The superheterodyned signals, now at frequencies and respective phases(f-f(1))/O and (f-2f(1))/psi, are again mixed to generate a signal of frequency and phase f(1)/psi. This the local oscillator signal exhibiting the phase difference occurring between two neighboring elements. The comparison between f(1)/psi and the local oscillator signal f(1)/O constitutes a measurement of the phase taper along the array and can be used for phasing of the signals in the array in a conventional manner, using phase shifters.

Instead of employing phase-shifting elements, a set of signals at the local oscillator frequency f(1), having phase angles psi, 2psi... (n-1)psi are generated. These signals are used for heterodyning the signals received by the different antenna elements. By using the phase-shifted signals for the mixing process, the signals from the different elements are all in phase after heterodyning and can be amplified through one common amplifier. The set of signals at frequency f(1) with the multiple phases of psi, f(1)/psi... f(1)/(n-1)psi are derived from the multiples of f(1)/O and f/psi. The signal f(1)/psi is phased through a multiplier H(2), generating signals 2f(1)/2(psi), 3f(1)/3psi, etc. By mixing 2f(1)/2psi with f(1)/O, 3f(1)/3psi with 2f(1)/O, etc., the signals f(1)/2psi, f(1)/3psi, etc., are obtained. This is performed in the set of mixers M''(1), M''(2), etc., shown at the upper right of the drawing.

The amplified common IF signal, at frequency and phase (f-f(1))/O, must now be properly phase shifted and distributed to the transmitting elements. This is performed in the following fashion. The signal from a stable local oscillator, STALO operating at frequency f(2), is mixed in a set of mixers M'''(1)...M'''(n) with th...