SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  AF071-147 (AirForce)
Title:  Compact Broadband Antennas
Research & Technical Areas:  Sensors, Electronics

  STATEMENT OF INTENT: This topic holds the greatest potential for meeting the technical needs of our warfighters supported by PEOs and Centers.
  Objective:  Develop a compact wideband (VHF to L Band) transmit/receive antenna with uniform gain over a wide azimuthal field of view for small aerial vehicles (UAV/AGM/Decoy).
  Description:  The operational bandwidth of some advanced airborne tactical RF systems requires the use of several antennas to cover multiple bands. In an effort to reduce real estate on the airborne systems for future additions, and cut down on interference between these antennas, innovative solutions that enhance RF efficiency and performance of small broadband antennas are of interest. These antennas must be designed for the small surface area of a typical small aerial vehicle (UAV/AGM/Decoy) but the invention is not limited on the airframe (i.e. may be installed in the nose, fins, conformal, etc.). The objective antenna should have the following features: (1) capable of omni-directional coverage in azimuth, (2) capable of operation over the frequency range of 30 to 2000 MHz with an instantaneous bandwidth of at least 700 Mhz, (3) transmit and receive capable, and (4) operation at high levels of efficiency (efficiency, gain, VSWR, good performance at the low end of the bands, etc.). The effort should analyze the predicted performance of the selected antenna (implemented in the vehicle’s airframe), dome material, and thermal and aerodynamic effects.

  PHASE I: Demonstrate proof-of-concept of antenna design using computer modeling tools or fabrication of a laboratory model antenna system with limited measured data.
  
  PHASE II: Develop, fabricate, and test a prototype (laboratory model) antenna and compare to design predictions. If a laboratory model was developed during Phase I, demonstrate further maturity of the design.

  DUAL USE COMMERCIALIZATION: Military application: A successful demonstration of this technology could lead to nulled antenna inferference and create an enhanced RF efficiency. Commercial application: The dual use potential will vary depending on the particular technology that is developed.

  References:  1 Mailloux, R. J., "Phased Array Antenna Handbook," Artech House, 1994 2. Mailloux, R. "Chapter 21: Conformal and Low-Profile Arrays." Antenna Engineering Handbook, McGraw-Hill, 1984 3. Carr, Joseph J., "Practical Antenna Handbook", 4th edition, McGraw-Hill (May 23, 2001) 4. P. Bhartia, Inder Bahl, R. Garg, A. Ittipiboon, "Microstrip Antenna Design Handbook", November 2000, Artech House 5. Kiuchi, E., "Tactical Cylindrical Active Phased Array Radar," 1996 IEEE International Symposium on Phased Array Systems and Technology, pp. 222-225, October 1996

Keywords:  Antenna, wideband, multi-band, conformal, munitions

Questions and Answers:
Q: Can you specify the diameter of the fuselage?
A: No stringent dimensions/sizes/shapes are specified. An 8-10 inch diameter fuselage might be used as point of reference.
Q: 1. In achieving the required omnidirectional coverage in azimuth, what ripple factor, or depth of nulls, (in dB) in the azimuth radiation pattern is allowed?

2. What requirement is placed on the elevation pattern?
A: 1. No pattern requirements have been defined. However, the gain remaining fairly constant with coverage and frequency is as important as the maximum gain.

2. The aerial vehicle will fly in a near level trajectory that also requires downward coverage (horizon to -45 degrees is desired).
Q: Can you specify (a) the gain, efficiency, polarization, and power handling requirements and (b) size constraints?
A: a) Polarization diversity (linear/ortho-linear, circular/ortho-circular) and capable of high power transmission/reception is preferred. No other specs defined at this point.

b) Antenna design should consider the small surface area of a typical small aerial vehicle (i.e.: 6ft wingspan, 10ft long). No location constraints at this point.
Q: Can you specify the surface or location of the aerial vehicle on which the antenna is to be mounted, e.g., the bottome surface or instrument pod of a UAV?
A: No restriction on antenna location given that is in accord with topic description/objectives. In general, airframe surface is mostly composite.
Q: Can you specify the diameter of the fuselage?
A: No stringent dimensions/sizes/shapes are specified. An 8-10 inch diameter fuselage might be used as point of reference.
Q: 1. In achieving the required omnidirectional coverage in azimuth, what ripple factor, or depth of nulls, (in dB) in the azimuth radiation pattern is allowed?

2. What requirement is placed on the elevation pattern?
A: 1. No pattern requirements have been defined. However, the gain remaining fairly constant with coverage and frequency is as important as the maximum gain.

2. The aerial vehicle will fly in a near level trajectory that also requires downward coverage (horizon to -45 degrees is desired).
Q: Can you specify (a) the gain, efficiency, polarization, and power handling requirements and (b) size constraints?
A: a) Polarization diversity (linear/ortho-linear, circular/ortho-circular) and capable of high power transmission/reception is preferred. No other specs defined at this point.

b) Antenna design should consider the small surface area of a typical small aerial vehicle (i.e.: 6ft wingspan, 10ft long). No location constraints at this point.
Q: Can you specify the surface or location of the aerial vehicle on which the antenna is to be mounted, e.g., the bottome surface or instrument pod of a UAV?
A: No restriction on antenna location given that is in accord with topic description/objectives. In general, airframe surface is mostly composite.

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