Houston Radar PD420 User Manual
Page 43 of 46
Appendix D: Recommended Enclosure for Open Frame
Radars
The PD420-OFD/PD420-OFD open frame radar needs to be enclosed in a weatherproof
enclosure for outside use. The following needs to be observed for optimal performance:
1.
The front face of the radar (PCB with the golden pads) is the antenna and is the
face that must point towards traffic.
2.
Any cover or window in front of the unit MUST be at least ¼” away from the
face.
3.
Do NOT spray any conformal coating, paint or other substance on the antenna.
4.
The optimum material to use as a front window is Lexan (Polycarbonate) plastic.
5.
The optimum thickness of the polycarbonate window is half wavelength at
24.125Ghz or about 3.5 to 3.7mm (0.137” to 0.146”) thick.
a.
Alternatively a thin window of any plastic material may be used. In this
case the maximum thickness should not exceed 1 mm (40 mils).
b.
Standard 0.25” thick Lexan should be avoided as it has particularly high
reflection coefficient due to this specific thickness.
6.
Other plastic materials may be used as a front window, but the optimum thickness
will wary with the material’s dielectric constant. Please contact us for details.
Note: for most applications a weatherproof potted version PD420-DFT/PD420-DFT is
recommended. An exception is a situation where internal space in the customer enclosure
is limited and cannot accommodate weatherproof radar.
