1. What is the current status of research on mm-Wave frequencies
What is the current status of research on mm-Wave frequencies? - in relation to health
Andrew W Wood
School of Health Sciences
Swinburne University of Technology
Melbourne, Australia

2. 5G and Millimetre waves
Designation
Frequency range
Wavelength range
L band
1 to 2 GHz
15 cm to 30 cm
S band
2 to 4 GHz
7.5 cm to 15 cm
C band
4 to 8 GHz
3.75 cm to 7.5 cm
X band
8 to 12 GHz
25 mm to 37.5 mm
Ku band
12 to 18 GHz
16.7 mm to 25 mm
K band
18 to 26.5 GHz
11.3 mm to 16.7 mm
Ka band
26.5 to 40 GHz
5.0 mm to 11.3 mm
Q band
33 to 50 GHz
6.0 mm to 9.0 mm
U band
40 to 60 GHz
5.0 mm to 7.5 mm
V band
50 to 75 GHz
4.0 mm to 6.0 mm
W band
75 to 110 GHz
2.7 mm to 4.0 mm
F band
90 to 140 GHz
2.1 mm to 3.3 mm
D band
110 to 170 GHz
1.8 mm to 2.7 mm
Current 5G deployment
? Future
N.B. mm waves have been around for a while (~1900: JC Bose), but only now being exploited in consumer technologies.

3. mm wave absorption by air
Strong absorption due to water and O2
Source: Wikipedia

4. Absorption by pure water
mm-waves = 103 mm
Source: Wozniak & Dera, 2007, Springer

5. Mm wave research: Herbert Fröhlich
1905 – 1991, University of Liverpool
Fellow of Royal Society
Proposed theory of coherent excitations in biological systems – region of 100 GHz, corresponding to mm waves
Several books, but Fröhlich & Kremer (1983) reports several experimental group’s findings
Some papers in Nature

6. Early key references
Webb & Dodds (1968). Inhibition of bacterial cell growth by 136 GHz microwave. Nature 218:
Grundler, Keilmann& Frohlich (1977). Resonant growth rate response of yeast cells irradiated by weak microwaves. Physics Letters A 62: GHz
Furia, Hill & Gandhi (1986). Effect of millimetre wave irradiation of growth of saccharomyces cerevisiae. IEEE Trans BME: 33: three frequency ranges between and GHz– No Effect

7. Work of Marvin Ziskin, MD
From initial work in obstetric ultrasound, went on to investigate mm-wave effects, particularly in skin: use in therapy
Recipient of BEMS d’Arsonval award in 2011
Key reference: Bioelectromagnetics 34:3-14 (2013)
Collaborators: M Zhadobov, S Alekseev, R Saulau, Y Le Drean
Mechanism: stimulation of a) nervous b) immune system

8. GHz tissue absorption
Above 10 GHz, tissue is strongly absorbent (Data from Gabriel)

9. Ziskin’s work on skin models
Skin thickness range 0.1 – 1.5 mm
Epidermis ~ 0.1 mm
Note sweat glands and hair follicles
Nerve endings are just below epidermis
Blood capillaries are also present in dermis
biology-forums.com

10. Skin models Multilayered models (for mm-wave frequencies)
Alekseev & Ziskin Bioelectromagnetics 28:331–339, 2007
Concluded: Model 1 OK for forearm, but 3 better; for palm skin, need 2 or more layers

11. Structure of cornea Thickness 0.5 – 0.8 mm Densely innervated
No blood vessels
Susceptible to ‘flash burn’ (welder’s flash) usually due to UV but also IR

12. US military and use of mm waves
Lots of papers & reports on military radar safety standards, from 1950s
Pakhomov et al. Lit. review. BEMS 19:393 (1998) – including extensive work in former USSR, esp. use in therapy
Work on ‘less than-lethal’ weapons. The Silent Guardian (95 GHz focussed beam, inflicting intense pain at distances of tens of metres)
Airport security scanning

13. Yuri Feldman – helical sweat glands
Phys Med Biol 54:3341 (2009)
Modelling (incorporating helices) and measurement from palm of hand
Modelling predicts 97 GHz
Other modelling predicts ~ 400 GHz

14. Biological changes?
Use for therapy: high success rates reported. Thermal?
No effects on gene expression: Ziskin & Zhadobov groups
Cellular proliferation: reduction of cancer metastasis reported in at least 3 studies
Effects on membranes: shape modification above 9 W/m2
Immune & inflammatory systems: increased rates of healing (as low as 1 W/m2)
Protein denaturation is chief thermal concern
See Wu, Rappaport & Collins (2015) doi: /MMM

15. Swinburne projects
Prediction & measurement of dielectric parameters for water & biological materials in range 1 GHz – 100 THz. Dielectric parameters of relevant biomaterials in this range.
Model of skin, including glands, hair follicles, rete ridges and moles. Ear canal model
SAR in RF workers in extreme conditions (including sweating and blood flow changes): effects of protective clothing
Public exposure to wireless technologies (using MVG EME SPY200 system)
Therapeutic tissue ablation modelling

16. Summary
Skin and eyes are regions of concern in regard to 5G frequencies (6 – 60 GHz) and beyond
Early concerns around proliferation of yeasts and bacterial spores unsubstantiated
Ziskin work raises possibility of non-thermal mechanisms, but heat most likely explanation (for therapy outcomes)
Could be resonant enhancement absorption due to skin structures
What we know in relation to standards: basic restrictions based on thermal mechs. OK, but absorption patterns still need to be determined. N.B. metric is PD, not SAR