## 4 Materials and Methods
### Conditions of Irradiation  
The schematic diagram of the experimental setup for MMW irradiation is illustrated in Figure 5. Yeast cells were spotted on the Agar medium prior to irradiation. The agar layer thickness was kept constant throughout (2 mL volume) on 35 mm polystyrene plates. Cells were exposed to specific frequencies of 85 GHz, 95 GHz, and 105 GHz at 5 dBm power for 6 h respectively. The irradiation experiment for each frequency involved six distinct experiments at the same cell density. MMW (85-110 GHz) were generated using a signal generator (N5183B, 9 kHz-20 GHz, Keysight Technology, Santa Rosa, CA, USA), and 6\(\times\) active frequency multiplier (QMM-311220025, Quinstar Tech Inc., Torrance, CA, USA). A standard gain pyramidal horn antenna (QWH-WPRROO, Quinstar Tech Inc.) was used for MMW emission. The power of transmitted waves from the horn was measured using an identical horn antenna and digital storage oscilloscope (DSO-X 2004A, Agilent Technology, Santa Clara, CA, USA). Distribution of relative energy across antenna aperture was measured using an open-ended waveguide (QWH-WPRROO, Quinstar Tech Inc.) in the near field (see Figure 6).  
Specific absorption rate (SAR) was calculated (Table 1, see in results). It was in range 3.48-2.08 W/kg involving the horn antenna and 43.05 W/kg for the irradiations with 85 GHz using the waveguide, respectively:  
\[SAR=\frac{P_{a}}{m}=\frac{P_{a}}{\rho V}=\frac{\frac{P_{a}}{S}}{\rho l} \tag{1}\]  
was used to calculate the \(SAR\) values where \(SAR\), \(P_{a}\), \(m\), \(\rho\), \(V\), \(S\), and \(l\) denote. Specific absorption rate, absorbed power, mass, density, volume, surface area and depth of medium irradiated respectively. As most of the radiation was probably absorbed by the agar rather than the cells, the total volume is more relevant than dry cell mass. Density \(\rho\) was considered approximately equal to water (997 kg/m\({}^{3}\)) and depth \(l\) used in the experiments was 4 mm. Cells were irradiated after being immersed on the agar.  
The penetration depth of 85-110 GHz MMW is very shallow, hence the exposed surface area and not the volume is considered. The appropriate exposure metric for MMW is therefore the power density, power per area (W/m\({}^{2}\)). Absorbed power \(P_{a}\) was calculated as:  
\[P_{a}=Incident\ Power-Reflected\ Power \tag{2}\]  
where \(\frac{P_{a}}{S}\) represents the power densities of the irradiations used (1.39 mW/cm\({}^{2}\) for horn antenna and 17.17 mW/cm\({}^{2}\) for the wave guide).  
Conceptualization, A.B. and S.L.-A.; methodology, A.B., S.R. and S.L.-A.; software, A.B., S.R., K.K. and S.L.-A.; validation, S.L.-A., K.K., J.L. and A.Y.; formal analysis, A.B., S.R., S.L.-A. and A.Y.; investigation, A.B. and S.R.; resources, S.L.-A., K.K., J.L. and A.Y.; data curation, A.B., S.R. and S.L.-A.; writing--original draft preparation, A.B.; S.R. and S.L.-A., writing--review and editing, A.B., S.R., S.L.-A., K.K. and A.Y.; visualization, A.B., S.R. and S.L.-A.; supervision, S.L.-A.; project administration, S.L.-A. and A.Y.; funding acquisition, S.L.-A., K.K., J.L. and A.Y. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Ariel Center for Applied Cancer Research.  
Not applicable.  
The authors acknowledge the Israeli Council for Higher Education (CHE) for fellowship.  
The authors declare no conflict of interest.  
Figure 6: Relative distribution of power across horn antenna aperture.