WO2022144540A1

WO2022144540A1 - Electromagnetic field strength meter

Info

Publication number: WO2022144540A1
Application number: PCT/GB2021/053417
Authority: WO
Inventors: Glynn Russell HUGHES
Original assignee: EMF Protection Limited
Priority date: 2020-12-29
Filing date: 2021-12-23
Publication date: 2022-07-07
Also published as: GB202020692D0; GB2602467B; GB2602467A

Abstract

A handheld electromagnetic field strength meter which has a number of antennas and detectors which are configured to detect electromagnetic fields within a corresponding number of different frequency ranges. The handheld electromagnetic field strength meter can be switched between different modes of operation in which the handheld electromagnetic field strength meter measures the strength of electromagnetic fields within the different frequency ranges. At least one of the frequency ranges may correspond to the so-called 5G high band (26GHz-70GHz) or millimetre wave (mmWave) band, thus enabling users to monitor frequency ranges significantly beyond the capabilities of existing handheld devices. Pairs of antennas and corresponding detectors are provided on respective modules, and the modules may be removed, repaired or replaced, or detection ranges of the handheld electromagnetic field strength meter changed by adding different modules.

Description

Electromagnetic Field Strength Meter

The present invention relates to the field of electromagnetic field monitoring. In particular, the present invention concerns improvements to electromagnetic field strength meters, and specifically handheld EMF monitors. In an embodiment of the invention a broadband electromagnetic field strength meter is provided which is capable of monitoring freguency ranges significantly beyond the capabilities of existing handheld devices.

Background to the invention

Individuals who suffer from electro-sensitivity find it desirable to monitor the environment for high freguency electromagnetic fields. By monitoring their exposure and/or identifying the source of the signal they can understand their environment better and take steps protect themselves, including eliminating or at least significantly reducing the measured freguency from the environment. Conventional consumer devices, and in particular handheld EMF meters and monitors, are costly and the Applicant has discovered that they are often unreliable and can suffer from accuracy and quality issues. Furthermore, no commercially available devices are able to measure so-called 5G high band (26GHz-70GHz) or millimetre wave (mmWave) signals, which at the Priority Date represent the next generation of wireless communication technology.

Currently, only industrial or laboratory-based instruments allow monitoring of such signals and these instruments are prohibitively expensive for individual consumers and/or are otherwise unsuitable for domestic applications. There is a need for a handheld device which is capable of meeting consumer demand for field strength monitoring in the relevant frequency ranges.

Accordingly, it is an object of at least one aspect of the present invention to obviate and/or mitigate one or more disadvantages of known/prior arrangements, and in particular to provide a handheld device capable of measuring a wide range of EMF frequencies spanning different communication bands. Further aims and objects of the invention will become apparent from reading the following description.

Summary of the invention

According to a first aspect of the invention, there is provided a handheld electromagnetic field strength meter comprising: a plurality of antennas; and a plurality of detectors; wherein at least one of the plurality of antennas and at least one corresponding detector are configured to detect electromagnetic fields within a first frequency range; wherein at least one other of the plurality of antennas and at least one corresponding detector are configured to detect electromagnetic fields in a second frequency range different from the first frequency range; and wherein the handheld electromagnetic field strength meter comprises means to switch between a first mode of operation in which the handheld electromagnetic field strength meter measures the strength of electromagnetic fields within the first frequency range and a second mode of operation in which the handheld electromagnetic field strength meter measures the strength of electromagnetic fields within the second frequency range.

Optionally, the first frequency range is 40 MHz to 10 GHz. Optionally, the second frequency range is 10 GHz to 40 GHz. Optionally, the second frequency range is 10 GHz to 70 GHz. Optionally, the second frequency range is 8 GHz to 30 GHz.

Preferably, at least one other of the plurality of antennas and at least one corresponding detector is configured to detect electromagnetic fields in a third frequency range different from the first and second frequency ranges, and wherein the handheld electromagnetic field strength meter comprises means to switch between a first, second and third modes of operation in which the handheld electromagnetic field strength meter measures the strength of electromagnetic fields within the first, second and third frequency ranges respectively.

Optionally, the first frequency range is 40 MHz to 10 GHz. Optionally, the second frequency range is 10 GHz to 40 GHz. Optionally, the third frequency range is 10 GHz to 70 GHz.

Preferably, in the first frequency range the respective detector(s) comprise a logarithmic radio frequency power detector. Preferably, in the second and/or the third frequency range the respective detector(s) comprise root mean squared radio frequency power detector(s). Optionally, pairs of antennas and corresponding detectors are provided on respective modules. For example, a first module may comprise an antenna and a detector configured to detect electromagnetic fields within the first frequency range, and a second module may comprise an antenna and a detector configured to detect electromagnetic fields within the second frequency range. Optionally, a module may comprise a plurality of pairs of antennas and corresponding detectors. For example, the second module may further comprise an antenna and a detector configured to detect electromagnetic fields within the third frequency range.

Preferably, the handheld electromagnetic field strength meter comprises means to output the measured electromagnetic field strength.

Preferably, the handheld electromagnetic field strength meter comprises an LCD screen. Preferably, the LCD screen is configured to display the measured electromagnetic field strength in predetermined units, for example pW/m².

Alternatively, or additionally, the handheld electromagnetic field strength meter comprises an LED display. Preferably, the LED display is configured to display the measured electromagnetic field strength according to a predetermined or sliding scale. The LED display may comprise an array or other plurality of LEDs. Optionally, the LED display comprises at least one green, one yellow and one red LED indicative of low, medium and high electromagnetic field strengths.

Alternatively, or additionally, the handheld electromagnetic field strength meter comprises a speaker. Preferably, the speaker is configured to produce an audible signal indicative of the detected electromagnetic field strength and/or the frequency of the/a measured electromagnetic field.

Preferably, the handheld electromagnetic field strength meter comprises input means to control the handheld electromagnetic field strength meter. Preferably, the input means is configured to switch between the first and second (and third) modes of operation of the handheld electromagnetic field strength meter. Optionally, the input means comprises a rotary encoder with a button. Alternatively, the input means comprises one or more switches. Alternatively, the input means comprises a touch screen. The input means to control the handheld electromagnetic field strength meter may be integrated with a display means to output the measured electromagnetic field strength. Optionally, the handheld electromagnetic field strength meter comprises a microcontroller.

Preferably, the microcontroller is configured to receive data from the detectors and determine corresponding electromagnetic field strengths. Preferably, the microcontroller is configured to output the determined electromagnetic field strengths via the output means.

Preferably, the handheld electromagnetic field strength meter comprises a memory. The memory may be integral to the microcontroller. Preferably, the handheld electromagnetic field strength meter is configured to store settings of the handheld electromagnetic field strength meter in the memory. Preferably, the handheld electromagnetic field strength meter is configured to store electromagnetic field strength values in the memory.

Optionally, the handheld electromagnetic field strength meter comprises a battery.

Alternatively, or additionally, the handheld electromagnetic field strength meter comprises a power connector to receive power from an external source. The handheld electromagnetic field strength meter may be configured to charge the battery from the external source.

Optionally, the handheld electromagnetic field strength meter comprises a housing. The housing may contain one or more apertures for one or more input and/or output means. Optionally, the housing comprises a protective casing, which may comprise rubber or silicone.

According to a second aspect of the invention, there is provided a method of measuring the strength of electromagnetic fields, the method comprising operating the handheld electromagnetic field strength meter of the first aspect.

Optionally, the method comprises switching between the first and second (and third) modes of operation of the handheld electromagnetic field strength meter.

Optionally, the method comprises calibrating the handheld electromagnetic field strength meter.

Embodiments of the second aspect of the invention may comprise features corresponding to the preferred or optional features of any other aspect of the invention or vice versa. Brief of the drawings

There will now be described, by way of example only, embodiments of aspects of the invention with reference to the drawings, of which:

Figure 1 is a high-level system diagram showing in schematic form the main components of an exemplary Electromagnetic Field strength meter;

Figure 2 shows in schematic form a general outline of the location of certain components of the EMF strength meter on PCB;

Figure 3 is a flow diagram showing the operation of the EMF strength meter;

Figure 4 is a flow diagram showing the menu structure of a user interface of the EMF strength meter; and

Figure 5 illustrates an enclosure in which the EMF strength meter is housed (a) in naked form and (b) with a protective cover applied.

Detailed description of preferred embodiments

As discussed in the background to the invention above it is desirable to be able to measure, in real-time, Electromagnetic Field (EMF) strength across a broad range of frequencies, ideally spanning all of the EMF frequencies to which a user is likely to be exposed in the home. As also discussed in the background to the invention above, existing handheld EMF meters and monitors are costly but often unreliable and inaccurate, and none are able to measure so-called 5G or millimetre wave (mmWave) signals.

An exemplary EMF strength meter will now be described, followed by a description of the operation of the EMF strength meter in the context of a software flow, and a description of a menu structure of an exemplary user interface which helps to illustrate certain preferred and optional features of the invention.

EMF Strength Meter

The Applicant has developed an EMF strength meter which is capable of field strength monitoring in the frequency range from 200MHz - 70GHz and display the results both visually and audibly.

Figure 1 illustrates in schematic form the main components of the EMF strength meter 101. There are provided three antennas 103A, 103B, 103C and associated detectors 105A, 105B, 105C tuned to three specific and separate frequency ranges. In this case, the frequency ranges are 40 MHz to 10 GHz, 10 GHz to 40 GHz and 40 to 70 GHz, respectively. This enables the EMF strength meter 101 to detect EMF signals across a wider range of frequencies than possible using existing consumer devices.

Note that in order to avoid missing any signals that might fall between the effective frequency ranges of the three antennas and associated detectors, it is foreseen that the ends of adjacent ranges might overlap to some extent. For example, the first antenna and detector might have an effective range of 40 MHz to 11 GHz, and the second antenna and detector might have an effective range of 9 GHz to 41 GHz. That way, signals at (in this example) 10 GHz are less likely to avoid detection. In another embodiment of the invention (not shown) the first antenna and detector have an effective range up to 10 GHz, and the second antenna and detector have an effective range of 8 GHz to 30 GHz. In the Figure 1 embodiment there are provided three separate antennas and detectors tuned to the specific frequency ranges above, however it is foreseen that any number of antennas and detectors may be provided, each tuned to certain frequency ranges (and not necessarily covering or limited to the range(s) above). For example it is known that broadband antennas and detectors may be capable of detecting signals over a wide range of frequencies however at lower sensitivity (overall) than narrowband antennas and detectors. Accordingly, a larger number of antennas and detectors with narrower frequency detection ranges might be employed to achieve higher sensitivity, although it is anticipated that there will be a commensurate increase in production costs. As such is it foreseen that more sensitive devices, with higher frequency resolution, can be provided at a higher price point, whereas a device with say only two antennas and detectors can be provided as an “entry level” device.

Furthermore, although in this embodiment the frequency range is selected manually (see below), the EMF strength meter may be configured to automatically switch frequency range. For example, it may switch to automatically highlight the frequencies at which one or more peaks in signal strength are detected. Alternatively, it might cycle through the available frequency ranges in a sequential and periodic manner.

In this embodiment, detector 105A is a logarithmic radio frequency (RF) power detector which, in combination with broadband antenna 103A, is able to measure RF power at frequencies up to 10 GHz. This is the practical limit at which commercially viable logarithmic RF detectors currently operate. In contrast, each of the detectors 105B, 105C comprise a chipset which uses an internal root-mean-square (RMS) function to compute the power of a detected radio frequency (RF) signal at higher frequencies than previously possible using conventional logarithmic RF power detectors (and 105A for example).

Accordingly, by combining a conventional logarithmic RF detector 105A (which is capable of measuring signals up to 10 GHz) with RMS detectors 105B, 105C (which are capable of measuring signals up to 40 GHz and 70 GHz (respectively)), and being able to switch between these measurement options, the EMF strength meter 101 can measure EMF strength across frequencies which are not measurable using currently available handheld devices.

Switching between measurement options or modes of operations (the terms may be used interchangeably) is by way of a rotary encoder 107 which provides an input to microcontroller 109. The microcontroller 109 receives data (or a signal) from the detectors 105A, 105B, 105C and from that data determines a corresponding electromagnetic field strength, which in this embodiment (see description further below) is a calibrated or “true” field strength. This field strength is then communicated to the user via a number of output means (see also Figure 2).

Three different output means are provided: an LCD display 111, an LED display 113 and a speaker 115. The LCD display shows the electromagnetic field strength in units of pW/m² (calibrated by the microcontroller 109). The LED display 113 provides an alternative visual representation of the electromagnetic field strength, in this case according to a predetermined or sliding scale with a green hue at a left-hand side of the LED display 113 indicative of a low electromagnetic field strength and a red hue at a right-hand side of the LED display 113 indicative of a high electromagnetic field strength. The speaker 115 provides an audible output which is again indicative of the electromagnetic field strength. For example, a higher pitch might signify the presence of a higher frequency and a higher volume might signify a higher field strength. It is also envisaged that the EMF strength meter 101 might produce an audible output resembling that of a Geiger counter.

In addition to an audible output representative of field strength, it is also envisaged that the speaker might provide audible feedback relating to the user’s interaction with the EMF strength meter, for example when accessing settings via a menu using the rotary encoder 107.

It will be understood that in different embodiments of the invention one or more of these output means may be dispensed with such that the field strength is communicated to the user in a more limited way. For example, the EMF strength meter might only provide an audible output, it might only provide a visual output on LEDs (which might be an array of LEDs where the number of LEDs illuminated scales with the field strength, or a simple traffic light style display comprising a green, a yellow and a red LED indicative of low, medium and high electromagnetic field strengths).

As discussed above, the EMF strength meter 101 is able to switch between measurement options. In this embodiment the switching is done via a rotary encoder 107 which enables the user to make selections (for example from a menu of options) by turning a wheel and then clicking an integrated button. In other embodiments it is foreseen that any manner of input means may be provided, including a variety of switches, or a touch screen which might be integrated with a display. Note that in Figure 2 the antenna 103A and detector 105A pair are comprised in a detector module 104A, and the antenna and detector pairs 103B,103C and 105B,105C are comprised in a detector module 104B/C. The first of these modules 104A may be termed a low-medium frequency detector module and the second of these modules 104B/C may be termed a medium-high frequency module as appropriate. These modules may be removed, repaired and/or replaced, and/or detection ranges of the EMF strength meter 101 changed by adding different modules.

To power the EMF strength meter 101 it is provided with a battery, which in this embodiment is a rechargeable 3.6 V Lithium ion battery 119. The EMF strength meter 101 can also be powered by an external power source via a power connector 121. A power management module 123 is configured to select and control the available power supplies, including facilitating charging the battery 119 with power received from the external source at the same time as powering the microcontroller 109 and other components of the EMF strength meter 101.

The basic operation of the EMF strength meter 101 described above is presented in Figure 3, which is a flow diagram showing the sequence of steps performed by the EMF strength meter 101 between switch on/power up 301 and outputting the measured field strength 315/317.

Firstly, the EMF strength meter is switched on 301, whereupon various clocks, ports and interrupts (as may be required by the microcontroller) are initialised 303. Previously used settings are read from memory 305, which might for example include the previously selected detector module and/or calibration data. The detector modules are then initialised 307 so that in the following steps measurements can begin.

The first step in a measurement and display/output loop is for the microcontroller to take a field strength reading from the selected detector module 309. The “true field strength” is then calculated 311 , taking into account calibration data. If sound is enabled 313, sound is generated responsive and relative to the field strength 315. The final step in the display/output loop is to display the field strength on the LCD display 317. User Interface and Menu Structure

Figure 4 illustrates an exemplary hierarchy or flow diagram showing the menu structure of a user interface of the EMF strength meter 101. Interaction with the user interface of the EMF strength meter 101 , which in this embodiment is presented textually on the LCD display 111 , is via the rotary encoder 107,401.

The first option set enables the user to select the frequency range 403. When this option is selected, the user is then able to choose between the low-medium frequency detector module 405 and the medium-high frequency detector module 407 by rotating the rotary encoder. When the push button is pressed the setting is stored 409 and the user returned to the top menu.

The second option set enables the user to switch sound on or off 409. The options selectable by rotating the rotary encoder include turning the sound on or off 411 , selecting an alternative sound option 413. Again, when the push button is pressed the setting is stored 415 and the user returned to the top menu.

The third option set enables the user to turn the sound volume up and down 417. The user is presented with a volume level indicator 419, and by rotating the rotary encoder in a first direction the volume is increased 421 and by rotating the rotary encoder in the opposite direction the volume is decreased 423. Again, when the push button is pressed the volume setting is stored 425 and the user returned to the top menu.

The fourth option set enables the user to clear any peak values stored in the EMF strength meter 427. The user is presented with single option to confirm the memory clear 429, and when the push button is pressed the memory is cleared and the user returned to the top menu.

The last option set enables the user to turn the EMF strength meter off 431. When the push button is pressed the user is presented with the options (selectable by rotating the rotary encoder) to cancel the power down request 433 or confirm the power down request 435. When the push button is pressed the EMF strength meter is turned off or enters a low power mode 437 (if the power down request is confirmed) or the user is returned to the top menu (if the power down request is cancelled). It will of course be understood that this is merely an example of a menu structure and the structure may take any form. Furthermore, navigating the menu structure may be performed by other means, such as switches or arrow buttons and an “enter” key, and/or various of the settings might be activated by standalone buttons representative of one or more presets. For example, there may be provided a standalone button which enables a user to cycle through the different frequency ranges measurable by the EMF strength monitor.

Figure 5 (a) shows an embodiment of the EMF strength meter within a housing 501, and Figure 5 (b) shows an embodiment of the EMF strength meter with an optional protective cover 503 applied to the housing 501 to offer drop protection and improve hand grip. The cover 503 may comprise rubber or silicone.

The invention provides a handheld electromagnetic field strength meter which has a number of antennas and detectors which are configured to detect electromagnetic fields within a corresponding number of different frequency ranges. The handheld electromagnetic field strength meter can be switched between different modes of operation in which the handheld electromagnetic field strength meter measures the strength of electromagnetic fields within the different frequency ranges. At least one of the frequency ranges may correspond to the so-called 5G high band (26GHz-70GHz) or millimetre wave (mmWave) band, thus enabling users to monitor frequency ranges significantly beyond the capabilities of existing handheld devices.

Throughout the specification, unless the context demands otherwise, the terms “comprise” or “include”, or variations such as “comprises” or “comprising”, “includes” or “including” will be understood to imply the inclusion of a stated integer or group of integers, but not the exclusion of any other integer or group of integers.

Various modifications to the above-described embodiments may be made within the scope of the invention, and the invention extends to combinations of features other than those expressly claimed herein.

Claims

Claims:

1. A handheld electromagnetic field strength meter comprising: a plurality of antennas; and a plurality of detectors; wherein at least one of the plurality of antennas and at least one corresponding detector are configured to detect electromagnetic fields within a first frequency range; wherein at least one other of the plurality of antennas and at least one corresponding detector are configured to detect electromagnetic fields in a second frequency range different from the first frequency range; wherein the handheld electromagnetic field strength meter comprises means to switch between a first mode of operation in which the handheld electromagnetic field strength meter measures the strength of electromagnetic fields within the first frequency range and a second mode of operation in which the handheld electromagnetic field strength meter measures the strength of electromagnetic fields within the second frequency range; and wherein pairs of antennas and corresponding detectors are provided on respective modules.

2. The handheld electromagnetic field strength meter of claim 1 , wherein a first module comprises an antenna and a detector configured to detect electromagnetic fields within the first frequency range, and a second module comprise an antenna and a detector configured to detect electromagnetic fields within the second frequency range.

3. The handheld electromagnetic field strength meter of claim 1 or claim 2, wherein the first frequency range is 40 MHz to 10 GHz.

4. The handheld electromagnetic field strength meter of any of claims 1 to 3, wherein the second frequency range is 8 GHz to 30 GHz, 10 GHz to 40 GHz or 10 GHz to 70 GHz.

5. The handheld electromagnetic field strength meter of any preceding claim, wherein at least one other of the plurality of antennas and at least one corresponding detector is configured to detect electromagnetic fields in a third frequency range different from the first and second frequency ranges, and wherein the handheld electromagnetic field strength meter comprises means to switch between a first, second and third modes of operation in which the handheld electromagnetic field strength meter measures the strength of electromagnetic fields within the first, second and third frequency ranges respectively.

6. The handheld electromagnetic field strength meter of claim 5, wherein the second module further comprises the at least one antenna and the at least one corresponding detector that are configured to detect electromagnetic fields in the third frequency range.

7. The handheld electromagnetic field strength meter of claim 5 or claim 6, wherein the third frequency range is 10 GHz to 70 GHz, or 40 GHz to 70 GHz.

8. The handheld electromagnetic field strength meter of any preceding claim, wherein in the first frequency range the respective detector(s) comprise a logarithmic radio frequency power detector.

9. The handheld electromagnetic field strength meter of any preceding claim, wherein in the second and/or third frequency range the respective detectors comprise root mean squared radio frequency power detectors.

10. The handheld electromagnetic field strength meter of any preceding claim, wherein the handheld electromagnetic field strength meter comprises means to output the measured electromagnetic field strength.

11. The handheld electromagnetic field strength meter of claim 10, wherein the handheld electromagnetic field strength meter comprises an LCD screen configured to display the measured electromagnetic field strength in predetermined units, for example pW/m².

12. The handheld electromagnetic field strength meter of claim 10 or claim 11 , wherein the handheld electromagnetic field strength meter comprises an LED display configured to display the measured electromagnetic field strength according to a predetermined or sliding scale.

13. The handheld electromagnetic field strength meter of any of claims 10 to 12, wherein the handheld electromagnetic field strength meter comprises a speaker configured to 15 produce an audible signal indicative of the detected electromagnetic field strength and/or the frequency of the/a measured electromagnetic field.

14. The handheld electromagnetic field strength meter of any preceding claim, wherein the handheld electromagnetic field strength meter comprises input means to control the handheld electromagnetic field strength meter.

15. The handheld electromagnetic field strength meter of claim 14, wherein the input means is configured to switch between the first and second (and optionally third) modes of operation of the handheld electromagnetic field strength meter.

16. The handheld electromagnetic field strength meter of claim 14 or claim 15, wherein the input means comprises a rotary encoder with a button.

17. The handheld electromagnetic field strength meter of any preceding claim, wherein the handheld electromagnetic field strength meter comprises a microcontroller configured to receive data from the detectors, determine corresponding electromagnetic field strengths, and output the determined electromagnetic field strengths via the output means.

18. The handheld electromagnetic field strength meter of any preceding claim, wherein the handheld electromagnetic field strength meter comprises a memory.

19. The handheld electromagnetic field strength meter of claim 18, wherein the handheld electromagnetic field strength meter is configured to store settings of the handheld electromagnetic field strength meter and/or electromagnetic field strength values in the memory.

20. The handheld electromagnetic field strength meter of any preceding claim, wherein the handheld electromagnetic field strength meter comprises a battery and/or a power connector to receive power from an external source.

21. The handheld electromagnetic field strength meter of any preceding claim, wherein handheld electromagnetic field strength meter comprises a housing comprising one or more apertures for one or more input and/or output means. 16

22. The handheld electromagnetic field strength meter of claim 21 , wherein the housing comprises a protective casing, which may comprise rubber or silicone.

23. A method of measuring the strength of electromagnetic fields, the method comprising operating the handheld electromagnetic field strength meter of any preceding claim.

24. The method of claim 23, further comprising switching between the first and second (and optionally third) modes of operation of the handheld electromagnetic field strength meter.

25. The method of claim 23 or claim 24, further comprising removing, repairing and/or replacing a module, and/or changing detection ranges of the handheld electromagnetic field strength meter by adding one or more different modules.