Engineering topics

Chernoff, R.

Publications and source records attributed to Chernoff, R..

3 records

NASA NTRS1980

Active retrodirective arrays for SPS beam pointing

The basic requirement of the SPS beam pointing system is that it deliver a certain amount of S-band (lambda = 12.5 cm) power to a 9.6 km diameter receiving rectenna on the ground. The power is transmitted from a 1.0 km diameter antenna array on the SPS, which is, for a rectenna at about plus or minus 40 deg. latitude, some 37.5x10 to the 6th power km distant. At the present time ARA's appear to be the best bet to realize this very stringent beam pointing requirement. An active retrodirective array (ARA) transmits a beam towards the apparent source of an illuminating signal called the pilot. The array produces, not merely reflects, RF power. Retrodirectivity is achieved by retransmitting from each element of the array a signal whose phase is the "conjugate" of that received by the element. Phase conjugate circuits and pointing errors in ARA's are described. Results obtained using a 2-element X-band ARA and an 8-element S-band ARA are included.

Chernoff, R.↗

NASA NTRS1980

Frequency translating phase conjugation circuit for active retrodirective antenna array

An active retrodirective antenna array which has central phasing from a reference antenna element through a "tree" structured network of transmission lines utilizes a number of phase conjugate circuits (PCCs) at each node and a phase reference regeneration circuit (PRR) at each node except the initial node. Each node virtually coincides with an element of the array. A PCC generates the exact conjugate phase of an incident signal using a phase locked loop which combines the phases in an up converter, divides the sum by 2 and mixes the result with the phase in a down converter for phase detection. The PRR extracts the phase from the conjugate phase. Both the PCC and the PRR are not only exact but also free from mixer degeneracy.

Chernoff, R.↗

NASA NTRS1978

Large active retrodirective arrays for solar power satellites

An active retrodirective array (ARA) transmits a beam toward the apparent source of an illuminating signal called the pilot. The array produces the RF power. Retrodirectivity is achieved by retransmitting from each element of the array a signal whose phase is the 'conjugate' of that received by the element. Application of the ARA to the solar power satellite concept has been proposed. A method of providing a reference phase is described, called 'central phasing', which eliminates the need for a rigid structure ordinarily needed in order to realize accurate retrodirectivity.

Chernoff, R.↗