The Howland Company has been involved in antenna range design since the company was founded. The first antenna ranges were outdoor ranges with tall towers at either end in order to minimize the effects of reflections from the range surface. Later the development of wide band microwave absorber allowed the design of indoor chambers, but it was only practical to test relatively low gain antennas in these facilities. The invention of the compact range gave engineers the ability to test high gain antennas indoors. Finally, the development of near-field techniques completed the portfolio of available choices.

In spite of all the techniques available to test antennas, there is not one general purpose range that will test every type of antenna. One must look at the characteristics of the antenna to be tested and decide which test method is most suitable.

The Howland Company's role has been to recommend the appropriate test method and then to design the physical parameters of the antenna range to meet the specific test requirements.

Outdoor Ranges

Indoor Ranges

Compact Ranges

Antenna Calibration Range for the F-22

Outdoor Ranges

Although simple in concept, there are many important details to consider in the design and layout of an outdoor antenna range.

Unfortunately, there is not a universal antenna range. Antenna ranges are designed for specific classes or types of antennas. A range designed for a high frequency fire control radar will not make accurate measurements of a low gain communications antenna.

The antenna range design starts with the antenna to be tested. From its size and operating frequency the antenna range designer can determine the range length, tower heights and source antenna characteristics.

And of course there are always tradeoffs to be made between the cost of the range and the acceptable level of uncertainty (precision) of the measurements the range is capable of making.

We have developed solutions for a range of clients, including Ford Aerospace, Motorola, Gabriel, and NASA's Jet Propulsion Lab. The Howland Company can also provide evaluations of existing outdoor ranges, including field probing and problem identification and resolution.

Antenna Range Complex, Motorola World Headquarters

The Howland Company designed this 5000-foot outdoor range as part of a project for the Deep Space Network operated by NASA's Jet Propulsion Lab. Pairs of 6-foot reflector antennas on the edge of the 26-meter parabolic reflector (inset right) and on a tower on the horizon down-range (inset left) were part of a gain measurement validation technique we developed and used to verify the performance of the large antenna system. (The white diode array between the two dishes on the tower was from a microwave power transmission experiment conducted several years earlier. Here is an interesting YouTube video about that experiment.)

Gabriel, now a part of General Dynamics SATCOM Technologies, asked The Howland Company to design a high-performance, outdoor antenna range for evaluation of antennas used on high-density, long haul common carrier systems. We designed the antenna range for measurement of low sidelobe levels and high front-to-back ratios. We also assisted Gabriel in obtaining local zoning approval for the facility. Once the instrumentation was installed, we evaluated the range to verify that it met predicted performance levels.

The Howland Company designed this 8000-foot automated test-on-transmit antenna range for Ford Aerospace to test Intelsat IV and V satellite antennas. We prepared a conceptual design for an automated, 10d²/λ, multi-band test facility; designed an anechoic test cubicle with a low return loss radome (inset); designed and built special instrumen-tation required for test-on-transmit and a 10,000-foot range cable to carry control signals in one direction and signal and reference data in the other. We also coord-inated test frequencies with existing commercial services and predicted the range's measurement uncertainty.

Download "The Design of an Automated, High-Accuracy Antenna Test Facility" by Jud Lyon and Ray Howland, IEEE I&M, March 1983 (816k PDF)

Indoor Ranges - Anechoic Chambers

Anechoic chambers are widely used by manufacturers of both defense and commercial products. Sometimes their purpose is to keep extraneous signals from interfering with a measurement, and at other times they are used to protect sensitive information from outside sources.

Tapered Anechoic Chamber, NSWC Dahlgren

The Howland Company performed 'before' and 'after' field probes and did extensive troubleshooting to bring this
100 x 27 x 27 foot chamber back to optimum performance after all of its RF absorber was replaced.

Indoor Range for RCS Measurements, Sandia National Labs

In the mid-eighties, The Howland Company designed one of the world's first indoor RCS ranges for Sandia National Labs. The facility includes a 110 ft x 42 ft x 26 ft (34m x 13m x 8m) anechoic chamber, compact range, and a host building with special provisions for seismic and environmental isolation. We prepared drawings and specifications related to the electromagnetic design; provided coordination between Sandia's facilities engineers, the building contractor, and the instrumentation system supplier; and wrote the range acceptance test procedure. We also designed and built a portable 12-foot NRL arch, which we used to perform on-site acceptance tests--normal, high incidence, and bistatic--on all 4300 pieces of RF absorber used in the facility. Click here for a news story about recent (2008) upgrades to this facility.

Compact Ranges

Originally developed by Scientific-Atlanta in cooperation with The Georgia Institute of Technology, the compact range has become a very useful tool for antenna, radome and RCS measurements.

In its simplest configuration, the compact range uses a parabolic reflector to generate a plane wave suitable for antenna measurements. Dual reflector systems were subsequently developed by March Microwave and MBB (now EADS Astrium) to enhance certain characteristics.

The Howland Company has been involved in numerous compact range projects over the last 30 years. These projects included compact ranges used for antenna, radome and RCS measurements. Typically we have been responsible for the overall electromagnetic design, including the design of the anechoic material and the shielding. It is not unusual for us to provide the overall design of the test article handling system.