Methods And Apparatus For Active Reflection

Abstract

An electromagnetic reflector includes an antenna that receives an incoming signal and that transmits an outgoing signal. A three-port device, such as a circulator, has a first port electromagnetically coupled to the antenna. An RF circuit has an input that is electromagnetically coupled to the second port of the three-port device and an output that is electromagnetically coupled to the third port of the three-port device. The RF circuit changes at least one of a gain and a phase of the incoming signal to generate a desired outgoing signal that passes through the three-port device to the antenna.

1 - 46 . (canceled) 
     
     
         47 . An electromagnetic reflector comprising:
 a) an antenna that receives an incoming signal and that transmits an active outgoing signal;   b) a three-port non-reciprocal device having a first port electromagnetically coupled to the antenna, a second port, and a third port; and   c) a circuit having an input electromagnetically coupled to the second port of the three-port non-reciprocal device and having an output electromagnetically coupled to the third port of the three-port non-reciprocal device, the circuit changing at least one of a gain and a phase of the incoming signal to generate an the active outgoing signal that passes through the three-port non-reciprocal device to the antenna, the active outgoing signal combining with a signal to form a desired outgoing signal.   
     
     
         48 . The electromagnetic reflector of  claim 47  wherein the signal combined with the active outgoing signal comprises a reflection signal. 
     
     
         49 . The electromagnetic reflector of  claim 47  wherein the three-port non-reciprocal device comprises an RF three-port non-reciprocal device and the circuit comprises an RF circuit. 
     
     
         50 . The electromagnetic reflector of  claim 47  wherein the three-port non-reciprocal device comprises an optical three-port non-reciprocal device and the circuit comprises an optical circuit. 
     
     
         51 . The electromagnetic reflector of  claim 47  wherein the three-port non-reciprocal device comprises a circulator. 
     
     
         52 . The electromagnetic reflector of  claim 47  wherein the circuit generates positive gain that amplifies the active outgoing signal relative to the incoming signal. 
     
     
         53 . The electromagnetic reflector of  claim 47  wherein the circuit generates negative gain that attenuates the active outgoing signal relative to the incoming signal. 
     
     
         54 . The electromagnetic reflector of  claim 47  wherein the circuit shifts a phase of the active outgoing signal relative to the phase of the incoming signal by 180 degrees. 
     
     
         55 . The electromagnetic reflector of  claim 47  wherein the circuit maintains a phase of the active outgoing signal to be substantially equal to the phase of the incoming signal. 
     
     
         56 . The electromagnetic reflector of  claim 47  wherein the circuit comprises at least one of an electrically controllable gain control circuit and an electrically controllable phase control circuit. 
     
     
         57 . The electromagnetic reflector of  claim 47  wherein the circuit generates at least one of a gain control signal and a phase control signal corresponding to the desired active outgoing signal. 
     
     
         58 . The electromagnetic reflector of  claim 47  wherein the antenna comprises a retro-reflective antenna array. 
     
     
         59 . The electromagnetic reflector of  claim 47  wherein the antenna comprises an omni-directional antenna. 
     
     
         60 . The electromagnetic reflector of  claim 47  wherein the antenna comprises a retro-reflecting antenna. 
     
     
         61 . The electromagnetic reflector of  claim 47  further comprising a means for determining a direction of the incoming signal. 
     
     
         62 . The electromagnetic reflector of  claim 47  further comprising a means for controlling a direction of the active outgoing signal relative to a direction of the incoming signal. 
     
     
         63 . The electromagnetic reflector of  claim 47  further comprising a signal processor having an output that is coupled to a control input of the circuit, wherein the signal processor generates a signal instructing the circuit to generate the active outgoing signal. 
     
     
         64 . The electromagnetic reflector of  claim 47  further comprising a passive reflector that reflects the incoming wave in a direction of the active outgoing signal. 
     
     
         65 . The electromagnetic reflector of  claim 47  further comprising an antenna matching circuit coupled between the antenna and the first port of the three-port non-reciprocal device, the antenna matching circuit reducing an antenna return loss. 
     
     
         66 . The electromagnetic reflector of  claim 47  further comprising a signal processor having an output that is coupled to a control input of the control circuit, the signal processor generating a signal that instructs the control circuit to generate a signal which generates the active outgoing signal.