Active Scattering for Bandwidth Enhanced MIMO

Abstract

An active scattering device comprises a set of N identical single chain RF devices functioning as repeaters or transponders, which are placed adjacent to each other and in parallel over an area of active scattering, where N is an integer ≥2. Each of the N identical RF devices includes a receiving aperture, having a first coverage, for receiving a first signal within the first coverage; and a transmitting aperture, having a second coverage, for re-radiating a second signal within the second coverage, the second signal being received by one of the respective receiving apertures of the N identical RF devices. In various embodiments, the active scattering device is configured to function as a reflective directional repeater/transponder, or a retro-directive repeater/transponder, or a 2-D directional repeater/transponder that is retro-directive in a first dimension and reflective in a second dimension perpendicular to the first dimension.

What is claimed is: 
     
         1 . An active scattering device comprising:
 a set of N identical single chain radio frequency (RF) devices functioning as repeaters or transponders, being placed adjacent to each other and in parallel over an area of active scattering, where N is an integer greater than or equal to 2, wherein each of the N identical single chain RF devices comprises:
 a receiving aperture, having a first coverage, for receiving a first signal within the first coverage; and 
 a transmitting aperture, having a second coverage, for re-radiating a second signal within the second coverage, the second signal being received by one of the respective receiving apertures of the N identical single chain RF devices, 
   wherein the N identical single chain RF devices are configured to function as a space-fed array supporting multiple users concurrently.   
     
     
         2 . The active scattering device of  claim 1 , wherein each of the N identical single chain RF devices functions as a repeater and further comprises:
 a bandpass filter coupled to the receiving aperture; and   an amplifier coupled to the bandpass filter and to one of the respective transmitting apertures of the N identical single chain RF devices.   
     
     
         3 . The active scattering device of  claim 1 , wherein each of the N identical single chain RF devices functions as a transponder and further comprises:
 a low-noise amplifier coupled to the receiving aperture;   a frequency converter coupled to the low noise amplifier;   a bandpass filter coupled to the frequency converter; and   an amplifier coupled to the bandpass filter and to one of the respective transmitting apertures of the N identical single chain RF devices.   
     
     
         4 . The active scattering device of  claim 1 , wherein the active scattering device is placed over the area of active scattering on a wall or a ceiling in a building or on a moving platform. 
     
     
         5 . The active scattering device of  claim 1 , wherein the N identical single chain RF devices are placed regularly at less than a half wavelength apart. 
     
     
         6 . The active scattering device of  claim 1 , wherein the respective receiving apertures of the N identical single chain RF devices are aligned in parallel on a first plane and the respective transmitting apertures are aligned in parallel on a second plane. 
     
     
         7 . The active scattering device of  claim 1 , wherein the N identical single chain RF devices are configured to function as a reflective directional repeater or a reflective directional transponder. 
     
     
         8 . The active scattering device of  claim 7 , wherein the N identical single chain RF devices are not physically interconnected, and wherein the respective receiving apertures of the N identical single chain RF devices are aligned horizontally and the respective transmitting apertures are aligned horizontally. 
     
     
         9 . The active scattering device of  claim 8 , wherein a width of the area of active scattering determines resulting beamwidths of reception beams and re-radiation beams of the active scattering device. 
     
     
         10 . The active scattering device of  claim 1 , wherein the N identical single chain RF devices are configured to function as a retro-directive repeater or a retro-directive transponder. 
     
     
         11 . The active scattering device of  claim 10 , wherein the N identical single chain RF devices are placed and identified in sequential order from i=1 to i=N, the respective receiving apertures of the N identical single chain RF devices being aligned in a direction and the respective transmitting apertures being aligned in the same direction, and wherein the receiving aperture of the i th  identical single chain RF device is coupled to the transmitting aperture of the (N+1−i) th  identical single chain RF device, where i=1, . . . , N. 
     
     
         12 . An active scattering device comprising:
 a set of N identical single chain radio frequency (RF) devices functioning as repeaters or transponders, being placed adjacent to each other and in parallel over an area of active scattering, where N is an even integer greater than 2, wherein each of the N identical single chain RF devices comprises:
 a receiving aperture, having a first coverage, for receiving a first signal within the first coverage; and 
 a transmitting aperture, having a second coverage, for re-radiating a second signal within the second coverage, the second signal being received by one of the respective receiving apertures of the N identical single chain RF devices, 
   wherein the N identical single chain RF devices are configured to function as a space-fed array supporting multiple users concurrently.   
     
     
         13 . The active scattering device of  claim 12 , wherein each of the N identical single chain RF devices functions as a repeater and further comprises:
 a bandpass filter coupled to the receiving aperture; and   an amplifier coupled to the bandpass filter and to one of the respective transmitting apertures of the N identical single chain RF devices.   
     
     
         14 . The active scattering device of  claim 12 , wherein each of the N identical single chain RF devices functions as a transponder and further comprises:
 a low-noise amplifier coupled to the receiving aperture;   a frequency converter coupled to the low noise amplifier;   a bandpass filter coupled to the frequency converter; and   an amplifier coupled to the bandpass filter and to one of the respective transmitting apertures of the N identical single chain RF devices.   
     
     
         15 . The active scattering device of  claim 12 , wherein the N identical single chain RF devices are placed over the area of active scattering on a wall or a ceiling in a building or on a moving platform. 
     
     
         16 . The active scattering device of  claim 12 , wherein the N identical single chain RF devices are configured to function as a two-dimensional (2-D) directional repeater or transponder that is retro-directive in a first dimension and reflective in a second dimension, the first and second dimensions being perpendicular to each other. 
     
     
         17 . The active scattering device of  claim 16 , wherein the N identical single chain RF devices are arranged into N/2 pairs of adjacent identical single chain RF devices, each of the N/2 pairs of adjacent identical single chain RF devices comprising:
 a first receiving aperture of a first identical single chain RF device, having a third coverage, for receiving a third signal within the third coverage;   a second receiving aperture of a second identical single chain RF device, having a fourth coverage, for receiving a fourth signal within the fourth coverage;   a first transmitting aperture of the first identical single chain RF device, having a fifth coverage, coupled to the second receiving aperture, for re-radiating the fourth signal within the fifth coverage; and   a second transmitting aperture of the second identical single chain RF device, having a sixth coverage, coupled to the first receiving aperture, for re-radiating the third signal within the sixth coverage.   
     
     
         18 . The active scattering device of  claim 17 , wherein the respective first receiving apertures of the N/2 pairs of adjacent identical single chain RF devices are aligned horizontally on a first line and the respective second receiving apertures of the N/2 pairs of adjacent identical single chain RF devices are aligned horizontally on a second line, and wherein the respective first transmitting apertures of the N/2 pairs of adjacent identical single chain RF devices are aligned horizontally on a third line and the respective second transmitting apertures of the N/2 pairs of adjacent identical single chain RF devices are aligned horizontally on a fourth line. 
     
     
         19 . The active scattering device of  claim 18 , wherein the N identical single chain RF devices are placed regularly at less than a half wavelength apart. 
     
     
         20 . The active scattering device of  claim 18 , wherein a width of the area of active scattering determines resulting beamwidths of reception beams and re-radiation beams of the active scattering device.