The antenna feed horns and switch array could be made the same way, allowing the antennas to be very low in cost. Besides the low cost, compact size and ruggedness, the Rotman lens antenna also offers very low throughput loss and sidelobe emissions. In the prototype developed by Peterson and Rausch, sidelobe power can be suppressed by a factor of one-thousand below the energy of the main beam. The power loss through the lens itself is less than 2 dB. Most antennas operating at millimeter wave frequencies use mechanical scanning or phase shifters, both of which have disadvantages. Mechanically steered antennas are slow in response and suffer reliability problems due to shock and vibration.
Phase shifters are costly to fabricate and introduce considerable RF losses.
By avoiding those drawbacks, the Rotman lens antenna could open new applications for millimeter wave radar. To be successful in some of the applications Rausch envisions, the antenna's operating frequency must be expanded, and the capability to scan in two dimensions added. Poor visibility caused by heavy fog can keep pilots from seeing enough of the runway to allow a safe landing. A synthetic vision system based on millimeter wave radar could produce images through the fog, allowing aircraft to land even when runways are obscured. To be affordable for cost-conscious airlines, such a system would require a reliable, compact and inexpensive antenna system.