Equipment that generates microwave radiation (MWR) spanning the frequency range of 300 MHz-100 GHz is becoming more common. While MWR lacks sufficient energy to break chemical bonds, the disagreement as to whether MWR exposure is detrimental to cellular dysfunction may be difficult to clarify using complex systems such as whole animals, cells, or cell extracts. Recently, the high frequency range of terahertz (THz) radiation has been explored and sources of radiation and its detectors have been developed. THz radiation is associated with the frequency interval from 100 GHz to 20 THz and constitutes the next frontier in imaging science and technology. In the present study, we investigated the effect of radiation in the low frequency THz range (100 GHz) on two defined molecular interactions. First, the interaction of soluble or immobilized calf alkaline phosphatase with the substrate p-nitrophenylphosphate and second, the interaction between an antibody (mouse monoclonal anti-DNP) and its antigen (DNP). Irradiation of enzyme either prior to addition of substrate or during the enzymatic reaction resulted in small but significant reductions in enzyme activity. These differences were not observed if the enzyme had previously been immobilized onto plastic microwells. Exposure of immobilized antigen to radiation did not influence the ability of the antigen to interact with antibody. However, irradiation appeared to decrease the stability of previously formed antigen-antibody complexes. Our data suggest that 100 GHz radiation can induce small but statistically significant alterations in the characteristics of these two types of biomolecular interactions.

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A single-pixel imaging remote sensor operating at 330 GHz is described. It is based on a frequency modulated continuous wave (FMCW) and aimed at detection of concealed objects for ranges up to 40 m. The system consists of 2 horn-lens antennas integrated with a homodyne transceiver. The synthesized linear FMCW signal at X-band is multiplied by a factor of 32 to generate the transmitted signal. An intermediate frequency (IF) signal obtained in the output port of the 2-nd harmonic mixer is employed for image processing. Distance measurements were made by performing data acquisition unit based on LabView interface and resulting in a range resolution about 1 cm. Examples of 2D and 3D images reconstructed with this sensor are presented.

The paper presents results of sensitivity estimations of the microwave sensor designed for controlling concentration of various mixture solutions. It consists of the resonator supporting TM010 mode with the axial glass tube filled with the solution under test. Concentrations of both organic (sugar, alcohol) and inorganic (NaCl, KMnO4 ) water solutions were determined with high accuracy. The sensitivity of the sensor in determination of NaCl is 0.4 dB/(mg/ml) within the concentration range 0 -1 %.It is about the two orders higher than sensitivity of the sensor based on near field dielectric resonator.