This paper introduces a microwave measurement setup using three microstrip antennas integrated with a microwave oscillator and Schottky-diode detectors used as bistatic microwave sensors. We have measured the microwave attenuation (water content) and the bistatic radar cross section (dimensions) of eggs having different time of storage (see Fig. 1). The measured attenuation for fresh egg is 8 - 10 dB at the frequency of 14.2 GHz, the variation with time is: dA [dB] equals -0.033T (days), thus nearly -1 dB/30 days. Our next program is to create a microwave equipment for automatic selection of old eggs. The basic arrangement and the results of our measurement are discussed.
Ferenc Volgyi, Ferenc Volgyi,
"Detection of subsurface water content of eggs using bistatic microwave sensors", Proc. SPIE 3752, Subsurface Sensors and Applications, (15 October 1999); doi: 10.1117/12.365726; https://doi.org/10.1117/12.365726