ACTIVE PHASED ARRAY ANTENNA FOR AIRCRAFT SURVEILLANCE SYSTEMS

• US 20080122693A1
• Filed: 08/08/2006
• Published: 05/29/2008
• Est. Priority Date: 08/08/2006
• Status: Active Grant

• Current Assignee: Garmin International, Inc. (Garmin Limited)
• Original Assignee: Garmin International, Inc. (Garmin Limited)
• Inventors: Mindrup, David T., Needham, Edward W., Blessing, John C.
• Granted Patent: US 7,439,901 B2
• Time in Patent Office: Days
• US Class Current: 342/368
• CPC Class Codes: G01S 13/933 of aircraft or spacecraft
• CPC Class Codes: G01S 2013/0254 Active array antenna
• CPC Class Codes: G01S 7/03 Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
• CPC Class Codes: G01S 7/4017 of HF systems
• CPC Class Codes: H01Q 1/28 Adaptation for use in or on aircraft, missiles, satellites, or balloons
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence

Abstract

An active antenna is provided that includes an antenna element for transmitting RF transmit signals at a predetermined effective radiated power (ERP). An antenna module is configured to be mounted to an aircraft, with the antenna element being mounted to the antenna module. A connector module is provided at the antenna module and is configured to be coupled to a communications link and receive electrical transmit signals from the communications link. A transmit path is provided within the antenna module and extends between the antenna element and the connector module. A power amplifier is provided on the antenna module along the transmit path. The power amplifier increases a power level of the electrical transmit signals, received from the communications link, by a predetermined amount sufficient to drive the antenna element to transmit the RF transmit signals at the predetermined ERP.

Claims

1. A TAS/TCAS active antenna apparatus, comprising:

an antenna element for transmitting TAS/TCAS interrogation signals at a predetermined effective radiated power (ERP) and for receiving TAS/TCAS interrogation response signals;

an antenna module configured to be mounted to an aircraft, the antenna module being mounted adjacent to the antenna element and coupled to the antenna element and a communications link to receive the TAS/TCAS interrogation signals from the communications link, the antenna module including

a receive path extending between the antenna element and the communications link, and

a transmit path extending between the antenna element and the communications link, the transmit path being different than the receive path;

a transmit power amplifier provided on the transmit path of the antenna module, the power amplifier increasing a power level of the TAS/TCAS interrogation signals received from the communications link by an amount sufficient to drive the antenna element to transmit the TAS/TCAS interrogation signals at the predetermined ERP; and

a receive power amplifier provided on the receive path of the antenna module, the receive power amplifier for increasing a power level of the received TAS/TCAS interrogation response signals before outputting the received signals to the communications link.

2. The apparatus of claim 1, further comprising a phased array having a plurality of the antenna elements that transmit and receive radio frequency signals.

3. The apparatus of claim 1, wherein the antenna module receives the TAS/TCAS interrogation signals from the communications link at a power level of less than 10 watts and the antenna module provides the TAS/TCAS interrogation signals to the antenna element at a power level over 10 watts.

5. The apparatus of claim 1, wherein the antenna module includes first and second circuit boards (CB), the first CB having the antenna element mounted thereon, the second CB having the power amplifiers mounted thereon.

6. The apparatus of claim 1, wherein the antenna module includes first and second circuit boards configured to be mounted to the exterior and interior of an aircraft, respectively.

7. The apparatus of claim 1, further comprising a coaxial line forming at least a portion of the communications link and conveying the TAS/TCAS interrogation signals to the antenna module at a power level of less than 10 watts.

9. The apparatus of claim 1, wherein the antenna module includes a calibration path extending between the antenna element and the communications link, the calibration path including an attenuation element for reducing a power level of a received TAS/TCAS interrogation response signal before outputting the received signal to the communications link.

11. The apparatus of claim 1, wherein the antenna module includes a calibration path, wherein the paths extend parallel to each other between the antenna element and the communications link.

12. The apparatus of claim 1, further comprising a remote transmit unit coupled to the communications link, the remote transmit unit outputting the TAS/TCAS interrogation signals over the communications link to the antenna module at a power level of less than 10 watts.

4. (canceled)

8. (canceled)

10. (canceled)

13-20. -20. (canceled)

21. A TAS/TCAS active antenna apparatus, comprising:

an antenna element mounted to an external surface of an aircraft for transmitting TAS/TCAS interrogation signals and receiving TAS/TCAS interrogation response signals;

an antenna module coupled to the antenna element and comprising

a transmit path having a transmit amplifier amplifying the TAS/TCAS interrogation signals to a first power level from a second power level, and

a receive path, parallel to the transmit path, and having a receive amplifier amplifying the TAS/TCAS interrogation response signals to a third power level from a fourth power level;

a bidirectional coaxial line coupled to the antenna module; and

a transmit and receive unit, mounted remotely from the antenna module and coupled to the coaxial line, generating the TAS/TCAS interrogation signals over the coaxial line at the second power level and receiving the TAS/TCAS interrogation response signals over the coaxial line at the third power level.

22. The apparatus of claim 21, wherein the antenna element receives the TAS/TCAS interrogation signals from the antenna module at the first power level, the first power level being greater than the second power level which is received by the antenna module from the transmit and receive unit.

23. The apparatus of claim 21, wherein the transmit and receive unit receives the TAS/TCAS interrogation response signals from the antenna module at the third power level, the third power level being greater than the fourth power level which is received by the antenna module from the antenna element.

24. The apparatus of claim 21, wherein the antenna module further includes a calibration path parallel to both the transmit path and the receive path, the calibration path having an attenuator attenuating calibration signals from a fifth power level to a sixth power level.

25. The apparatus of claim 21, the antenna module further including selector switches located at either end of the paths for selecting between the paths.

26. The apparatus of claim 21, wherein the coaxial line carries the TAS/TCAS interrogation signal from the transmit and receive unit toward the antenna element at a lower power level than that used by the antenna element.

27. The apparatus of claim 21, wherein the coaxial line carries the TAS/TCAS interrogation response signal to the transmit and receive unit from the antenna element at a higher power level than that received at the antenna element.

28. The apparatus of claim 21, wherein the first power level is greater than 40 watts and the second power level is less than 10 watts.

29. The apparatus of claim 21, wherein the third power level is greater than 4 watts and the fourth power level is less than 4 watts.

30. The apparatus of claim 24, wherein the fifth power level is greater than 10 watts and the sixth power level is less than 10 watts.