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Mast Antenna Coupler



OBJECTIVE: Develop a modular, enclosed antenna coupler to assist in the radio frequency (RF) testing of imaging mast antennas. 

DESCRIPTION: The Navy needs the ability to perform an on-site pier-side test of the antenna mast without environmental interference. Currently, no commercial technologies are capable of performing this function. Today’s submarine electronic warfare (EW) suite, which includes the outboard sensors, RF distribution, and inboard electronics support measures (ESM) equipment, require system grooms as part of a maintenance cycle. Conducting open air RF testing as a part of these grooms can be difficult due to the congested nature of the electromagnetic (EM) spectrum in and around Navy ports. The submarine community is interested in an antenna coupler housed in a shroud enclosure to improve radiated end-to-end testing and calibration routines for ESM systems. Utility in grooming the submarine imaging masts is of primary interest. The ability to absorb or scatter incident energy in order to simulate free space is most frequently seen in an anechoic chamber. This technology, along with shielding mechanisms, can be harnessed to create an apparatus capable of testing sensitive RF antennas and associated RF paths in EM environments that would normally preclude such testing. The shroud should be capable of accepting radio signals from a supplied RF source and radiating the signals into the mast mounted antennas in order to validate the full functionality of ESM system. The shroud should be capable of operating from 2MHz to 50GHz while maintaining modularity such that it could be adapted to accommodate multiple types of masts. The shroud has to receive and radiate RF signals with a vertical polarization, in the operating frequencies provided above, along a 360-degree azimuthal field of view at the horizon. The shroud should be capable of testing GPS (L1, L2, and L5) and Iridium functionality at zenith and provide a minimum of 70dB of attenuation from the ambient environment over the entire operational frequency range. In compliance with MIL-STD-810G this unit should operate during various weather conditions i.e. rain (506.5-1 – 506.5-11), high wind speeds, humidity up to near 100% (507.5-1 – 507.5A-1), salt air environments (509.5-1 – 509.5-10), and temperatures varying from -10°C to +55°C (501.5-1 – 501.5-13 and 502.5-1 – 502.5-9). The unit should be only tall enough to accommodate the antennas under test without exceeding 600% of the antenna diameter or 250% of the antenna height. The unit should be portable, waterproof, and tearproof o the greatest extent possible, to include a transit case to hold and transport the unit when not in use. The Phase II and Phase III efforts will likely require secure access, and NAVSEA will process the DD254 to support the contractor for personnel and facility certification for secure access. The Phase I effort will not require access to classified information. Work produced in Phase II may become classified. Note: The prospective contractor(s) must be U.S. Owned and Operated with no Foreign Influence as defined by DOD 5220.22-M, National Industrial Security Program Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Security Service (DSS). The selected contractor and/or subcontractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances, in order to perform on advanced phases of this contract as set forth by DSS and NAVSEA in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material IAW DoD 5220.22-M during the advance phases of this contract. 

PHASE I: Develop a concept for an enclosure describe in the description where an antenna mast is isolated such that RF interferers outside the enclosure do not interfere with an ongoing test. Demonstrate the feasibility of the concept in meeting the Navy needs and establish that the concept can be developed into a useful product for the Navy. Based on technical analysis, determine the ideal solution for achieving the performance goals. The Phase I Option, if awarded, should include the initial design specification and capabilities description to build a prototype in Phase II. Develop a Phase II plan. 

PHASE II: Based on the result of Phase I and the Phase II Statement of Work (SOW), develop and deliver a prototype system with the capability to isolate an antenna mast while the shroud is equipped and perform the functions stated in the description. Evaluate the prototype to determine its capability in meeting the performance goals defined in the description and in the Phase II SOW. Prepare a Phase III SOW to transition the technology developed for Navy use. It is probable that the work under this effort will be classified under Phase II (see Description section for details). 

PHASE III: Support the Navy in transitioning the shroud for Navy use if Phase II is successful and receives approval. Develop a system according to Phase III SOW for evaluation to determine effectiveness in an operational relevant environment. Support the Navy for test and validation to certify and qualify the system for grooming the AN/BLQ-10B (V) and associated program of record sensors under PMS 435 Submarine Electromagnetic Systems Program Office. This technology could be beneficial to commercial antenna companies that use anechoic chambers to perform tests of their products in order to verify it is functioning properly. 


1: Abdelaziz, Abdelmonem Abdelaziz. "Improving the Performance of An Antenna Array by Using Radar Absorbing Cover." Progress In Electromagnetics Research Letters 1 (2008): 129-38. Web.

2:  Fenn, J. "Analysis of phase-focused near-field testing for multiphase-center adaptive radar systems." IEEE Transactions on Antennas and Propagation, August 1992, vol. 40, no. 8, pp. 878-887.

3:  Kraz, Vladimir. "Near-Field Methods of Locating EMI Sources." Compliance Engineer, May/June 1995.

KEYWORDS: Radio Frequencies From Submarine Masts; Electromagnetic Compatibility (EMC); Radar Cross Section (RCS); Anechoic Chamber; Antenna Mast Shroud; Electronic Warfare 


Keven Goncalves 

(401) 832-6381 

Robert Dougenik 

(401) 832-5610 

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