High frequency measurements at 50 MHz-10 GHz were performed for the first time using interdigitated electrodes on a low temperature co-fired ceramic substrate to analyze fungal spores. Wet and dry spore generation methods were evaluated and tested with two different fungal species. The dry generation method was found feasible for RF measurements, since the component capacitance increased 14-21% in the 2-6 GHz range, but for the wet generation method the capacitance decreased only slightly (<1%). Based on these initial results the RF measurements have the capacity to evaluate the quantity of fungal spores but not to identify their species.
2. Venkatesh, M. S. and G. Raghavan, "An overview of microwave processing and dielectric properties of agri-food materials," Biosystems Engineering, Vol. 88, No. 1, 1-18, 2004.
doi:10.1016/j.biosystemseng.2004.01.007
3. Est, A. V. D., C. Hager-Braun, W. Leibl, G. Hauska, and D. Stehlik, "Transient electron paramagnetic resonance spectroscopy on green-sulfur bacteria and heliobacteria at two microwave frequencies," Biochimica et Biophysica Acta, Vol. 1409, No. 2, 87-98, 1998.
doi:10.1016/S0005-2728(98)00152-2
4. Ong, K., J. Bitler, C. Grimes, L. Puckett, and L. Bachas, "Remote query resonant-circuit sensors for monitoring of bacteria growth: Application to food quality control," Sensors, 219-232, 2002.
doi:10.3390/s20600219
5. Reponen, T., J. Lockey, D. I. Bernstein, S. J. Vesper, and G. K. Hershey, "Infant origins of childhood asthma associated with speci¯c molds," Journal of Allergy and Clinical Immunology, 639-944, 2012.
doi:10.1016/j.jaci.2012.05.030
6. Schmechel, D., R. L. G¶orny, J. P. Simpson, T. Reponen, S. A. Grinshpun, and D. M. Lewis, "Limitations of monoclonal antibodies for monitoring of fungal aerosols using Penicillium brevicompactum as a model fungus," Journal of Immunological Methods, Vol. 283, 235-245, 2003.
doi:10.1016/j.jim.2003.09.012
7. Sivasubramani, S. K., R. T. Niemeier, T. Reponen, and S. A. Grinshpun, "Fungal spore source strength tester: Laboratory evaluation of a new concept," Science of the Total Environment, Vol. 329, 75-86, 2004.
doi:10.1016/j.scitotenv.2004.03.007
8. Tuhkala, M., J. Juuti, and H. Jantunen, "Determination of compolex permittivity of surfactant treated powders using an open-ended coaxial cavity resonator," Powder Technology, Vol. 256, 140-145, 2004.
9. Tuhkala, M., J. Juuti, and H. Jantunen, "An indirectly coupled open-ended resonator applied to characterize dielectric properties of MgTiO3-CaTiO3 powders," Journal of Applied Physics, Vol. 115, 184101-1, 2014.