Directive, electrically-small UWB antenna system and method
A directive electrically small antenna (DESA) process and method employs multipole synthesis to implement directive electrically small multipole antennas with ultra-wideband (UWB) stable antenna patterns. Although lossy, embodiments have adequate efficiency to work as receive antennas in the high ambient noise environment of the HF band and below. Employing a process dubbed “antenna regeneration,” energy may be circulated within an antenna by means other than resonance. This enables multiple decade UWB response without the efficiency penalties inherent to traditional resistively-loaded antenna systems. Regenerative antennas can simultaneously achieve the performance of high Q resonant antennas and the bandwidth of resistively loaded antennas.
1. An electrically-small directive antenna system comprising a twin lead transmission line and at least one load and further comprising a multipole configuration of radiation centers, the radiation centers emitting or receiving signals, and the radiation centers phased so as to yield a substantial cancellation of the signals in at least one direction resulting in a directive antenna pattern and wherein the twin-lead transmission line is impedance matched to at least one load, wherein the twin-lead transmission line is characterized by a length greater than a separation distance, and wherein the length is less than a quarter wavelength at a frequency of operation.
2. The electrically-small directive antenna system of claim 1 wherein the load is regenerative.
3. The electrically-small directive antenna system of claim 1 further including a cross-over.
4. The electrically-small directive antenna system of claim 1 further including an impedance transformer.
5. The electrically-small directive antenna system of claim 1 further including a second transmission line embedded within the twin-lead transmission line.
6. The electrically-small directive antenna system of claim 1 wherein the multipole is a quadrupole.
7. The electrically-small directive antenna system of claim 1 wherein the multipole is an octupole.
8. An electrically-small directive antenna system comprising a feed point, a load, and a twin-lead transmission line between the feed-point and the load, wherein the twin-lead transmission line is impedance matched to the load, wherein the twin-lead transmission line is characterized by a length greater than a separation distance, and wherein the length is less than a quarter wavelength at a frequency of operation.
9. The electrically-small directive antenna system of claim 8 further including at least one cross-over.
10. The electrically-small directive antenna system of claim 8 further including an impedance transformer.
11. The electrically-small directive antenna system of claim 8 further including a second transmission line embedded within the twin-lead transmission line.
12. The electrically-small directive antenna system of claim 8 wherein the load is a regenerative load.
13. The electrically-small directive antenna system of claim 12 wherein the regenerative load employs rectification.
14. The electrically-small directive antenna system of claim 12 wherein the regenerative load employs transformer coupling.
15. The electrically-small directive antenna system of claim 12 wherein the regenerative load employs a phase shifter.
16. The electrically-small directive antenna system of claim 12 wherein the regenerative load employs amplification.
17. The electrically-small directive antenna system of claim 8 wherein the load and the feed point form a multipole configuration of radiation centers phased so as to yield a substantial cancellation of the signals in at least one direction resulting in a directive antenna pattern.