77 GHz stepped lens with sectorial radiation pattern as primary feed of a lens-based CATR
Résumé
We describe the design, fabrication and measurements of an axisymmetric dielectric lens, featuring a sectorial radiation pattern at 77 GHz. It will be used as the primary feed of a lens-based compact antenna test range (CATR). Due to symmetry of revolution, the sectorial lens profile can be designed in one dimension by using phase only control. The phase variation is echoed on the lens depth. The resulting stepped lens is simulated using France Telecom Orange Labs SRSRD software (¿in-house¿ software developed for dielectric axisymmetric radiating structures) and measured in an anechoic chamber at 77 GHz. Two lenses were fabricated with different materials: PVC and polyurethane, respectively. Good agreements were obtained between simulations and measurements. Less than 0.2 dB ripple in the central beam are obtained for the polyurethane lens although relatively high secondary lobes occur at 11°. Comparisons between the near field of a CATR illuminated by a small horn providing a uniform amplitude taper and the sectorial lens are conducted using numerical simulations. Results show that on-axis oscillations are reduced from 6 to 1 dB with the sectorial lens.
Mots clés
- Compact antenna test range (CATR)
- antenna testing
- lens antennas
- millimetre wave antennas
- stepped lens
- sectorial radiation pattern
- primary feed
- lens-based compact antenna test range
- axisymmetric dielectric lens
- phase only control
- phase control
- dielectric lens
- France Telecom Orange Labs SRSRD software
- Software measurement
- Telecommunication control
- Testing
- Antenna feeds
- Antenna measurements
- Fabrication
- Optical design
- Antenna radiation patterns
- Dielectric measurements
- Lenses
- bandwidth 77 GHz
- numerical simulations