How do I design an antenna for operation at 140 GHz for wireless backhaul?
Designing an antenna for 140 GHz wireless backhaul requires achieving high directivity (typically 40-45 dBi) to overcome the high free-space path loss. The three primary architectures are Cassegrain reflector antennas (25-40 cm diameter dishes providing 40-48 dBi gain), dielectric lens antennas (HDPE or Rexolite lenses fed by a planar antenna), and planar phased arrays (enabling electronic beam steering but limited by losses at 140 GHz). At 140 GHz with lambda = 2.14 mm, a 30 cm dish provides approximately 42 dBi gain. The surface accuracy must be better than lambda/20 (approximately 100 micrometers). The waveguide interface is WR-6.5 or WR-5.1.
High-Gain Antenna Options for D-Band Wireless Backhaul
The antenna is critical for D-band backhaul because the high free-space path loss (141 dB at 2 km) demands substantial antenna gain.
Common Questions
Frequently Asked Questions
What surface accuracy is needed for a D-band reflector antenna?
For less than 1 dB gain loss at 140 GHz, the surface RMS error should be below lambda/20 = 107 micrometers. This is readily achieved with CNC-machined aluminum.
Can I use a flat-panel antenna for D-band backhaul?
Yes. Planar slot array antennas can achieve 30-35 dBi gain at 140 GHz in a flat form factor.
How narrow is the beam at D-band with a typical backhaul antenna?
A 30 cm dish at 140 GHz produces a 3 dB beam width of approximately 0.5 degrees.
Keep Reading
Related Questions
Glossary