User's Guide

FUJITSU COMPONENT LIMITED
6
 The directivity is the maximum in Z-direction. Please embed FWM7RAZ01
according to the direction to detect.
 The misdetection will occur if there is a vibrating or moving obstacle between
antenna and object. The radio characteristics is influenced if there is a moving
metal or radio wave absorbent.
Please consider these factors to determine the layout.
3-3. Gain of Rx circuitry
Voltage gain from power feed point of Rx antenna(LNA input) to IF amplifier output is
calculated by the formula (2).
Fig. 4 Gain of Rx circuitry


 



[Vrms] ………………… (2)
Using P
r
value calculated at Example (adult man) in section 3-1, the output voltage at
IF1(I) and IF2(Q) is resulted as,
V
if
= 1.35 [mVrms]
It is recommended to implement the external amplifier before the signal processing of
FWM7RAZ01 IF output since IF output voltage (amplitude) level is very low in example.
Please calculate the necessary gain with considering the distance to object and size of
object at the implementation of the external amplifier.
Refer to 3.1
Voltage
Conversion
PA
LNA
Moving Object
IF
AMP
V
if
P
r
470Ω
Mixer