How do I select a connector type for operation above 40 GHz?
mmWave Connector Selection
Millimeter wave connector selection involves a smaller set of choices than microwave frequencies, but the stakes are higher. Each connector interface introduces more loss at mmWave because the smaller dimensions increase the contact resistance relative to the signal level, and any imperfection in the interface creates a larger electrical discontinuity relative to the wavelength.
| Parameter | Semi-Rigid | Conformable | Flexible |
|---|---|---|---|
| Loss (dB/m at 10 GHz) | 0.8-2.5 | 1.0-3.0 | 1.5-5.0 |
| Phase Stability | Excellent | Good | Fair |
| Bend Radius | Fixed after forming | Hand-formable | Continuous flex OK |
| Shielding (dB) | >120 | >90 | >60-90 |
| Cost (relative) | 2-5x | 1.5-3x | 1x |
Frequently Asked Questions
What about waveguide at these frequencies?
Waveguide is preferred for permanent installations above 40 GHz due to lower loss. WR-22 (33-50 GHz), WR-15 (50-75 GHz), WR-12 (60-90 GHz), and WR-10 (75-110 GHz) provide excellent performance. Coaxial connectors are used where wideband or multi-band capability is needed.
How fragile is the 1.0mm connector?
Very. The center pin diameter is 0.007 inches (0.18mm), smaller than a human hair. Misalignment during mating can bend or break the pin. Always use alignment guides, never force a connection, and inspect with a microscope before mating. Cost per connector: $300-600.
Is there anything above 110 GHz in coax?
Experimental 0.8mm connectors extend to 145 GHz, and 0.6mm connectors have been demonstrated to 200 GHz. These are not yet commercially standardized. Above 110 GHz, waveguide (WR-8, WR-6, WR-5, WR-4, WR-3) is the standard interconnect technology.