Radome Testing at NSI-MI Technologies’ Range
Leverage NSI-MI Technologies’ years of experience in the
antenna and radome test business. These test and
measurement facilities are located in our United States
headquarters near Atlanta, Georgia. We have dedicated
radome testing equipment and instrumentation that can
be applied to a wide range of requirements, from basic
DO-213 testing to custom military requirements that
push the limits of today’s measurement techniques.
NSI-MI’s has recently tested radomes of many sizes and requirements such as C-130 and F-15 radomes. Our insistence on measurement integrity and culture of close customer interaction ensures that quality and safety is maintained throughout the program.
- Cross-industry expertise from DO-213 to full military requirements
- Includes all the necessary test facilities, test equipment and test personnel
- State-of-the-art ranges at our Atlanta test facilities
- Quality equipment, expert staff and flexibility
NSI-MI’s in-house compact range facility with a 6ft cylindrical quiet zone includes a full suite of RF and microwave instrumentation and data analysis tools with dedicated radome positioning equipment. This allows us to accommodate a wide variety of radome sizes and provide rapid performance testing up to 94 GHz, all in an environmentally consistent and secure indoor facility.
Chamber Size: 24 ft wide x 40 ft deep x 25 ft tall with adjacent control room Frequency Range: 2 to 94 GHz Data Acquisition: Fully-automated system for all range configurations, controlled by an MI-3000 Data Acquisition and Analysis Workstation Compact Range Amplitude Variation: 0.5 dB amplitude taper Phase Variation: Less than 10 degrees Test Zone: Cylindrical 4 ft (1.2 m) diameter x 4 ft (1.2 m) length - Expandable to 6 ft (1.8 m) x 5 ft (1.5 m), 1.0 dB amplitude taper Positioning Equipment Equipment: Configurable radome ring and antenna positioner. Many alternative positioning components and fixtures available. Maximum Test Loads: Up to 1000 lbs
Transmission Efficiency is the percentage of microwave energy that passes through a radome, typically measured over various angular regions (which usually represent the area of the radome actually used by the radar system). It is measured by comparing power levels received by a test antenna under two different conditions. A reference measurement is made with the radome off, then again after installation of the radome over the radar antenna. The resulting data is plotted over the surface of the radome. While ideally transparent, all radomes will have losses as the RF signal passes through it due to a combination of reflections, diffraction, absorption, refraction and depolarization.
Beam Deflection (BD) / Boresight Shift (BS)
Beam Deflection is the change in the direction of propagation of the microwave signal as it passes through the radome. If one considers the geometry associated with the tracking of a fast moving enemy target or terrain avoidance for a low flying, fast moving aircraft, even very small angular errors introduced by the radome can have significant effects. (For test antennas with a tracking null, the term “boresight shift” is often used interchangeably with Beam Deflection. Beam Deflection can then be a term reserved for the case of a sum beam.)
Reflectivity is the change in the magnitude of the reflection coefficient at the port of the radar antenna which is caused by the presence of the radome. This is measured using a reflectometer with a remote head. The reflection coefficient is measured before and after the radome is installed, with the antenna pointing out into a reflection-less environment (such as an anechoic chamber or an outdoor range). Ideally, this measurement is independent of pointing direction of the radar antenna.
Antenna Pattern Distortion
Pattern distortion is the change to the radar antenna radiation pattern caused by the presence of the protective radome. Patterns are taken with and without the radome present. Various analyses can be made to assess the changes to the pattern shape, including: beam width, side lobe levels, peak/ null location, lobe imbalance, null fill, etc. This requires that the radar antenna rotate with the radome to maintain a particular antenna to radome aspect as the antenna pattern is measured.
Instrumentation is calibrated to NIST standards, providing confidence in the accuracy of tests performed at our facility. Periodically, we conduct a range probe using a phase/amplitude probe system to ensure electromagnetic quality in the frequency bands specified.