US 7,006,039 B2 · Microwave self-phasing antenna arrays for secure data transmission & satellite network crosslinks

Abstract

A high-directivity transponder system uses a dual system of a retrodirective array transmitting a data signal peak toward an interrogator source, and a self-null-steering array transmitting a null toward the interrogator source and a jamming signal elsewhere, resulting in high S/N reception at the interrogator source and avoidance of interception. Integrating modulators would allow each array to transmit different data while the spectra of the transmitted signals are identical, thus disabling interception. The system enables secure point-to-point communications and can be used for short-distance wireless data transmission systems such as wireless LAN and RFID servers. As another aspect, self-steering signal transmission is employed for randomly oriented satellites using circularly polarized, two-dimensional retrodirective arrays. Quadruple subharmonic mixing is used as an effective means of achieving phase conjugation when a high-frequency LO is not feasible or inapplicable. These features may be used for small-satellite communications, secure tactical communications, search and rescue, enemy location fixing and tracking, UAV command and control, forest fire detection, marine-based tracking, and many other applications requiring secure communications with high signal directivity.

Claims17

Dependent claims

A secure data transmission system for transmitting a data signal with high directivity toward a target while greatly reducing the likelihood of interception, comprising:

(a) a self-phasing retrodirective array for receiving an interrogating signal from the target and transmitting a data signal beam with a peak directed back toward the target;
and
(b) a self-null-steering array for receiving the interrogating signal from the target and transmitting, in conjunction with said retrodirective array, a jamming signal with a null directed toward the target and the jamming signal in other directions,
whereby the target can receive the data signal peak superimposed with the jamming signal null to maximize signal-to-noise (SNR) ratio in reception while the jamming signal is sent in the other directions.

1 more element

A system for secure crosslink communications in a network of small-platform transponders moving in space, comprising:

(a) a plurality of small-platform transponders each having a retrodirective antenna array for detecting the direction of an incoming interrogator signal and sending a response signal with a peak directed back toward the direction of the interrogator signal;
and
(b) said plurality of small-platform transponders operating together as a network of transponders by each one of said transponders establishing and maintaining a reliable crosslink with the other transponders without a priori knowledge of their positions by intermittently sending an interrogator signal to one or more other transponders and having the one or more other transponders send a response signal back to the one transponder,
wherein each one of said network of transponders has a dual array system including a self-phasing retrodirective array for receiving an interrogating signal and transmitting a data signal beam with a peak directed back toward the interrogator position, and
a self-null-steering array for receiving the interrogating signal and transmitting, in conjunction with said retrodirective array, a jamming signal with a null directed toward the interrogator position.

2 more elements

Dependencies are inferred from the claim text.

Microwave self-phasing antenna arrays for secure data transmission & satellite network crosslinks

Life of this patent

Microwave self-phasing antenna arrays for secure data transmission & satellite network crosslinks

Life of this patent

Abstract

Claims17