WO2018042347A1 - Antenna for underwater radio communications - Google Patents
Antenna for underwater radio communications Download PDFInfo
- Publication number
- WO2018042347A1 WO2018042347A1 PCT/IB2017/055217 IB2017055217W WO2018042347A1 WO 2018042347 A1 WO2018042347 A1 WO 2018042347A1 IB 2017055217 W IB2017055217 W IB 2017055217W WO 2018042347 A1 WO2018042347 A1 WO 2018042347A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- frequency
- antenna device
- directional
- antenna
- radiation pattern
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q1/00—Details of, or arrangements associated with, antennas
- H01Q1/04—Adaptation for subterranean or subaqueous use
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/22—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the orientation in accordance with variation of frequency of radiated wave
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
- H01Q9/04—Resonant antennas
- H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole
- H01Q9/20—Two collinear substantially straight active elements; Substantially straight single active elements
Definitions
- the present disclosure relates to an antenna for underwater radio communications and respective operation method, in particular to an antenna device for underwater radio communications comprising a frequency-tunable circuit, said circuit being tunable between a first frequency and a second frequency for obtaining a variable directional radiation pattern by the antenna device, in order to select a directional radiation pattern of the antenna device for improving the radio signal coupling with another antenna device.
- RF systems can overcome some of the limitations of both acoustic and optical systems. They have the advantage of not being affected by turbidity, operate in non-line-of- sight, are immune to acoustic noise and allow high bandwidths (up to 100 Mbit/s) at very close range.
- Freshwater conductivity can range from 0.005 to 0.05 S/m, the actual value increasing with salinity and temperature. Thus, seawater has a higher conductivity, with an average of 4 S/m.
- the relative permittivity ( ⁇ ⁇ ) of water depends upon several factors like water temperature, salinity and propagation frequency and it can be described by the Debye model or by the Cole-Cole equation.
- ⁇ ⁇ The relative permittivity of water depends upon several factors like water temperature, salinity and propagation frequency and it can be described by the Debye model or by the Cole-Cole equation.
- freshwater becomes a conductor for frequencies below 11.1 MHz and in the case of seawater this transition occurs at 888 MHz.
- the wavelength is defined by:
- tuning said circuit between a first frequency and a second frequency for obtaining a variable directional radiation pattern (i.e. a variable preferred operation direction) by the antenna device.
- An embodiment of the frequency-tunable circuit is a circuit comprising an adjustable-capacity capacitor connected in series or parallel with the antenna such that the resonant frequency of the antenna is adjustable. This adjustment may be carried out by a microprocessor or microcontroller.
- Another embodiment of the frequency-tunable circuit is a circuit which is tunable by a data processing device executing computer program instructions embodying one of the disclosed methods.
- An embodiment, for communicating with another antenna device comprises tuning said circuit to select a directional radiation pattern of the antenna device for improving the radio signal coupling between the antenna devices, in particular for maximizing the radio signal coupling between the antenna devices.
- the directional radiation pattern of the antenna device for one of the two frequencies is directional and the directional pattern of the antenna device for the other of the two frequencies is omnidirectional.
- said first frequency and a second frequency are predetermined according to the saltwater-freshwater content of the water such that the directional radiation pattern of the antenna device for one of the two frequencies is directional and the directional pattern of the antenna device for the other of the two frequencies is omnidirectional.
- the directional radiation pattern of the antenna device has a 90° shift between the first frequency and the second frequency.
- An embodiment comprises continuously tuning said circuit between the first frequency and the second frequency
- the directional pattern of the antenna device is continuously tuned between the first frequency and the second frequency.
- An embodiment comprises tuning said circuit in discrete steps between the first frequency and the second frequency
- the directional pattern of the antenna device is tuned in discrete steps between the first frequency and the second frequency.
- the first frequency is lower than 11.1 MHz and a second frequency is higher than 11.1 MHz, such that the directional radiation pattern of the antenna device for first frequency is directional and the directional radiation pattern of the antenna device for the second frequency is omnidirectional.
- the first frequency is lower than 888 Mhz and the second frequency is higher than 888 MHz
- the directional radiation pattern of the antenna device for first frequency is directional and the directional radiation pattern of the antenna device for the second frequency is omnidirectional.
- the first frequency is lower than ll.lMhz and the second frequency is higher than 888 MHz
- the directional radiation pattern of the antenna device for first frequency is directional and the directional radiation pattern for second frequency is omnidirectional, independently of the antenna device being submerged in fresh water or salt water.
- the antenna device is a dipole antenna or a loop antenna.
- the antenna device is used in an IEEE 802.11 protocol network.
- an antenna device for underwater radio communications comprising a frequency-tunable circuit, said circuit being tunable between a first frequency and a second frequency for obtaining a variable directional radiation pattern (i.e. a variable preferred operation direction) by the antenna device.
- An embodiment is arranged to periodically tune said circuit to select a directional radiation pattern of the antenna device for improving the radio signal coupling with another antenna device, in particular for maximizing the radio signal coupling with another antenna device.
- the said periodic tuning can be performed using a sweep, for example, every 10 seconds (see fig. 8).
- the tuning must be performed simultaneously by the two antenna devices (emitter and receiver), so that both antenna devices always use the same frequency.
- a default communication frequency (fa) shall be known by both antenna devices.
- Periodically both antenna devices will tune their circuits with a frequency sweep (fl-f2) known by both antenna devices, either continuous or discrete.
- a discrete frequency step can be defined for example between 1 MHz and 5 MHz to be used in the frequency sweep. Using a discrete frequency step facilitates keeping the two antennas in sync during the frequency sweep.
- the frequency sweep normally covers from the first frequency (fl) to the second frequency (f2), preferably with a total sweep duration much shorter than the period between said periodic tunings, for example, 100 ms, such that the communication throughout is not substantially affected by the time lost in this.
- the tuning is performed, one or both of the antenna devices can register the received signal strength.
- the results are analysed by one of the antenna devices (the master antenna device) and a decision is made on whether to tune the said circuit to another frequency.
- the decision depends on whether a frequency was found where the received signal strength is higher than the received signal strength at the current frequency, or the average of the received signal strength between both antenna devices is higher than the received signal strength at the current frequency.
- the decision is then communicated by the master antenna device to the other antenna device (slave), normally through said default or currently used frequency, so that both antenna devices will change to the same new frequency (fb).
- the process is preferably repeated periodically and the new frequency (fb) may then change subsequently to another new frequency (fc), and so on.
- the antenna device is arranged to periodically tune said circuit to select a directional radiation pattern of the antenna device for improving the radio signal coupling with another antenna device, by periodically making a frequency sweep in synchronized frequency between both antennas and selecting a frequency from said frequency sweep that maximizes signal strength coupling between said two antennas.
- a discrete frequency step can be defined between 1 MHz and 5 MHz to be used in the frequency sweep.
- both antenna devices will periodically tune their circuits to the neighbouring frequencies immediately above (f2) and below (fl) the current frequency, by iterative improvements, considering a discrete frequency step that can be defined for example between 1 MHz and 5 MHz (see fig. 9).
- a default communication frequency (fa) shall be known by both antenna devices.
- the tuning period can be for example 10 seconds.
- the next frequency to be used shall be decided by the master antenna device.
- the decision depends on whether the received signal strength at any of the tested frequencies (fl, f2) is higher than the received signal strength at the previous frequency (fa), or the average of the received signal strength between both antenna devices is higher at the tested frequencies than the received signal strength at the previous frequency.
- the process is preferably repeated periodically and the new frequency (fb) may then change subsequently to another new frequency (fc), and so on.
- the antenna device is arranged to periodically tune said circuit to select a directional radiation pattern of the antenna device for improving the radio signal coupling with another antenna device, by periodically making a frequency test, in synchronized frequency between both antennas, of a lower frequency than the frequency currently being used and an higher frequency than the frequency currently being used, and selecting a frequency from said lower and higher frequencies that maximizes signal strength coupling between said two antennas.
- the lower and higher frequencies may have a discrete frequency step that can be defined for example between 1 MHz and 5 MHz above and below the frequency currently being used.
- multiple antenna devices co-exist in a given underwater scenario.
- the master antenna device can send information specifically targeted to a given slave antenna device or group of slave antenna devices. Since the physical location of the slave antenna devices can be known to the master antenna device, the master antenna device will select the targeted slave antenna by switching to a frequency where the radiation is substantially directed in the targeted direction, a step that must be preceded with a communication at said default frequency indicating the next frequency to be used, in order to synchronize the transmission.
- An embodiment is arranged to continuously tune said circuit between the first frequency and the second frequency, such that the directional pattern of the antenna device is continuously tuned between the first frequency and the second frequency.
- An embodiment is arranged to tune said circuit in discrete steps between the first frequency and the second frequency, such that the directional pattern of the antenna device is tuned in discrete steps between the first frequency and the second frequency.
- the first frequency is 834 kHz or 1.68 MHz
- the second frequency is 19 MHz or 30 Mhz.
- the first frequency is between 834 kHz - 1.68 MHz
- the second frequency is between MHz - 30 Mhz.
- the first frequency is 286 MHz or 453 MHz
- the second frequency is 1 GHz or 2.16 GHz.
- the first frequency is between 286 MHz - 453 MHz
- the second frequency is between 1 GHz - 2.16 GHz.
- Figure 4 Analysed antennas: dipole and loop.
- Figure 7 Current distribution in antennas at the resonant frequency: dipole and loop.
- Figure 8 Frequency adjustment method by periodic frequency sweep.
- Table I Dimensions of the loop antenna for the three different types of media at three different frequencies.
- Table II Dimensions dipole antenna for the three different types of media at three different frequencies.
- Table III Radiation pattern for the dipole antenna for the three different media and for the three different frequencies.
- Table IV Radiation pattern for the loop antenna for the three different media and for the three different frequencies.
- Table V Radiation patterns for the loop antenna near the transition from conductive to dielectric media in freshwater.
- Table VI Radiation patterns for the loop antenna near the transition from conductive to dielectric media in seawater.
- the antennas are a loop antenna with a radius of 16 cm and a 50 cm length dipole antenna.
- the two antennas are depicted in Fig. 4 and consisted of a simple 3 mm thick cooper wire, covered with an insulator with a thickness of 50 ⁇ and a relative permittivity of 3.
- Fig. 7 shows the current distribution in both antennas at the resonant frequency. In this disclosure it is considered a ⁇ /2 dipole and a large loop with a circumference length being ⁇ .
- TABLE III and TABLE IV show the radiation patterns for the loop antenna and for the dipole, respectively, with the antennas placed in the same orientation as in Fig. 4. Again we see the influence of the water conductivity on the performance of the antenna. In a dielectric medium the radiation pattern maximums are oriented in the z+ and z- directions, whereas in a conductive medium they are shifted by 90°, in the case of the loop antenna. A change in the radiation pattern can be observed also for the dipole when the medium becomes conductive.
- Other antenna types, and respective combinations will have the corresponding radiation behaviours, such that the disclosure is not limited to dipole or loop antennas, these being illustrative embodiments.
- the performance of two antennas in underwater media was analysed. It was seen that the main radiation parameters, such as the resonant frequency, the input impedance and the radiation pattern, change dramatically with the conductivity of the medium where the antenna is placed. Moreover, the radiation pattern changes with the resonance frequency, that is, in freshwater/seawater the same type of antenna can have different radiation patterns depending if the medium is dielectric or conductive at the antenna's resonant frequency. Therefore, we can take advantage of this fact to achieve the control of the radiation diagram of an antenna placed in a certain type of underwater media, by adjusting the resonant frequency of the antenna with a simple electronic circuit. This can be exploited to improve underwater communications, for example, between a moving AUV and a fixed platform, by continuously adjusting the radiation diagram to the most favourable as the AUV moves.
- the main radiation parameters such as the resonant frequency, the input impedance and the radiation pattern
- code e.g., a software algorithm or program
- firmware e.g., a software algorithm or program
- computer useable medium having control logic for enabling execution on a computer system having a computer processor, such as any of the servers described herein.
- Such a computer system typically includes memory storage configured to provide output from execution of the code which configures a processor in accordance with the execution.
- the code can be arranged as firmware or software, and can be organized as a set of modules, including the various modules and algorithms described herein, such as discrete code modules, function calls, procedure calls or objects in an object-oriented programming environment. If implemented using modules, the code can comprise a single module or a plurality of modules that operate in cooperation with one another to configure the machine in which it is executed to perform the associated functions, as described herein.
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- Variable-Direction Aerials And Aerial Arrays (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2017319594A AU2017319594A1 (en) | 2016-08-30 | 2017-08-30 | Antenna for underwater radio communications |
CA3033933A CA3033933A1 (en) | 2016-08-30 | 2017-08-30 | Antenna for underwater radio communications |
JP2019511773A JP6924821B2 (en) | 2016-08-30 | 2017-08-30 | Underwater wireless communication antenna |
EP17772769.0A EP3507857B1 (en) | 2016-08-30 | 2017-08-30 | Antenna for underwater radio communications and corresponding method and storage media |
US16/329,546 US11121446B2 (en) | 2016-08-30 | 2017-08-30 | Antenna for underwater radio communications |
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP16186459.0 | 2016-08-30 | ||
EP16186459 | 2016-08-30 | ||
PT10972616 | 2016-11-08 | ||
PT109726 | 2016-11-08 | ||
EP16198054.5A EP3291364A1 (en) | 2016-08-30 | 2016-11-09 | Antenna for underwater radio communications |
EP16198054.5 | 2016-11-09 |
Publications (1)
Publication Number | Publication Date |
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WO2018042347A1 true WO2018042347A1 (en) | 2018-03-08 |
Family
ID=59969199
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/IB2017/055217 WO2018042347A1 (en) | 2016-08-30 | 2017-08-30 | Antenna for underwater radio communications |
Country Status (3)
Country | Link |
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AU (1) | AU2017319594A1 (en) |
CA (1) | CA3033933A1 (en) |
WO (1) | WO2018042347A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114584156A (en) * | 2020-12-02 | 2022-06-03 | 杭州海康威视数字技术股份有限公司 | Monitoring device and communication control method thereof |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
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WO2016012738A1 (en) * | 2014-07-22 | 2016-01-28 | Kabushiki Kaisha Toshiba | Antenna and method of manufacturing an antenna |
-
2017
- 2017-08-30 CA CA3033933A patent/CA3033933A1/en not_active Abandoned
- 2017-08-30 WO PCT/IB2017/055217 patent/WO2018042347A1/en unknown
- 2017-08-30 AU AU2017319594A patent/AU2017319594A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2016012738A1 (en) * | 2014-07-22 | 2016-01-28 | Kabushiki Kaisha Toshiba | Antenna and method of manufacturing an antenna |
Non-Patent Citations (7)
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"ANTENNA THEORY: ANALYSIS AND DESIGN", 1 January 2005, JOHN WILEY AND SONS, HOBOKEN, NEW JERSEY, ISBN: 978-0-471-66782-7, article CONSTANTINE A. BALANIS: "Chapter 4 - Linear Wire Antennas and Chapter 5 - Loop Antennas", pages: 151 - 281, XP055369936 * |
F. TEIXEIRA; J. SANTOS; L. PESSOA; M. PEREIRA; R. CAMPOS; M. RICARDO: "Evaluation of Underwater IEEE 802.11 Networks at VHF and UHF Frequency Bands using Software Defined Radios", PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON UNDERWATER NETWORKS & SYSTEMS, WUWNET '15, 2015 |
F. TEIXEIRA; P. FREITAS; L. PESSOA; R. CAMPOS; M. RICARDO: "Evaluation of IEEE 802.11 Underwater Networks Operating at 700 MHz, 2.4 GHz and 5 GHz", PROCEEDINGS OF THE 9TH ACM INTERNATIONAL CONFERENCE ON UNDERWATER NETWORKS & SYSTEMS, WUWNET, vol. 14, 2014 |
FILIPE TEIXEIRA ET AL: "Evaluation of IEEE 802.11 Underwater Networks Operating at 700 MHz, 2.4 GHz and 5 GHz", PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON UNDERWATER NETWORKS %SYSTEMS, WUWNET '14, 12 November 2014 (2014-11-12), New York, New York, USA, pages 1 - 5, XP055369689, ISBN: 978-1-4503-3277-4, DOI: 10.1145/2671490.2674571 * |
INACIO S I ET AL: "Antenna design for underwater radio communications", OCEANS 2016 - SHANGHAI, IEEE, 10 April 2016 (2016-04-10), pages 1 - 6, XP032909526, DOI: 10.1109/OCEANSAP.2016.7485705 * |
S. JIANG; S. GEORGAKOPOULOS: "Electromagnetic wave propagation into fresh water", JOURNAL OF ELECTROMAGNETIC ANALYSIS AND APPLICATIONS, vol. 3, no. 07, 2011, pages 261, XP055369693, DOI: doi:10.4236/jemaa.2011.37042 |
X. CHE; I. WELLS; G. DICKERS; P. KEAR; X. GONG: "Re-evaluation of RF electromagnetic communication in underwater sensor networks", IEEE COMMUNICATIONS MAGAZINE, vol. 48, no. 12, 2010, pages 143 - 151, XP011340440, DOI: doi:10.1109/MCOM.2010.5673085 |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN114584156A (en) * | 2020-12-02 | 2022-06-03 | 杭州海康威视数字技术股份有限公司 | Monitoring device and communication control method thereof |
CN114584156B (en) * | 2020-12-02 | 2024-05-10 | 杭州海康威视数字技术股份有限公司 | Monitoring device and communication control method thereof |
Also Published As
Publication number | Publication date |
---|---|
CA3033933A1 (en) | 2018-03-08 |
AU2017319594A1 (en) | 2019-02-28 |
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