Technical Specs
Table Of Contents
5 of 8
MSAN-010
AP11 Miniature K-Band Microwave Sensor
Application Note
V1.00
6. Pulsing the Voltage Supply
A constant DC power supply is typically supplied to the AP11 sensor module for continuous wave
(CW) mode operation. However, lower current consumption is acheivable by pulsing the input voltage
supply and a sample and hold circuit at the IF output. The AP11 sensor module can be powered by a
+V
in
pulse train of 2 KHz pulse repetition frequency (PRF) with a pulse width as narrow as 10 µsec.
Sensitivity of the module may be reduced when operating with narrow pulses.
The module start up time (settling time) is within 500 nsec, and the off time takes up to 600 nsec.
During these periods, the module output could be noisy. Hence the detector should avoid analyzing
signals close to these transition periods.
User should ensure that the PRF should be more than twice that of the signal frequency for proper re-
construction of the Doppler signal.
7. Placing the module in enclosure
A suitable plastic material with both lower dielectric constant and lower loss tangent (i.e., ABS,
Polycarbonate) is preferred. Microwaves penetrate through many plastics without significant loss as
long as it does not have direct contact with the antenna patch surface. In comparison, metal and water
results in significant reflection of microwaves. Therefore any metallic materials or metal plated
plastics in front of the antenna will negatively affect the performance of the sensor.
Sensitivity of the sensor can be affected by the thickness of the plastic enclosure and the spacing
between the antenna and the enclosure. Depending on the dielectric constant of the material and the
operating frequency of the sensor, the required enclosure thickness and sensor-enclosure distance can
vary. For typical ABS enclosures, we recommend a distance of 4-6 mm between the sensor and the
enclosure. This distance can be fine-tuned for optimum performance. The enclosure thickness can be
between 0.5 to 8 mm, depending on mechanical requirements. Details are presented in Figure 7.
CAUTION!
Plugging-in the module into an active power supply may not itself cause any damage, but any
accidental short to ground during this process may cause component damage in the module.
It is therefore recommended that power supply to be SWITCHED OFF first before
connecting the modules.