Ionic fluid antenna

Aspects of the disclosure are directed to an apparatus for providing an ionic fluid antenna. The apparatus may include a body configured to contain an ionic fluid, an acoustic transducer coupled to the body, and a power supply coupled to the acoustic transducer that is configured to drive the acoustic transducer in accordance with at least one frequency. Aspects of the disclosure are directed to an apparatus for providing an ionic fluid antenna used in secure communications, comprising: a body configured to contain an ionic fluid, an acoustic transducer coupled to the body, and a power supply coupled to the acoustic transducer that is con figured to drive the acoustic transducer based on an encryption of data using polarized photons for quantum key distribution.

BACKGROUND

Antennas are used in a variety of applications, such as in communications equipment. Antennas tend to be relatively large or bulky, consuming a significant portion of the footprint/space associated with such equipment. Additionally, the tuning range of such antennas tends to be limited, due in part to the components/devices that are used in constructing the antenna. Over that tuning range there exists gaps where no coverage is provided, representing a loss in terms of antenna performance/efficiency.

The communications may be vulnerable to being intercepted by third parties (e.g., by parties outside of one or more intended recipients of the communications). Additional measures are needed in order to ensure the privacy and security of communications.

BRIEF SUMMARY

Aspects of the disclosure are directed to an apparatus for providing an ionic fluid antenna, comprising: a body configured to contain an ionic fluid, an acoustic transducer coupled to the body, and a power supply coupled to the acoustic transducer that is configured to drive the acoustic transducer in accordance with at least one frequency.

In further embodiments of the foregoing aspect, the aforesaid apparatus may include additional elements or characteristics alone or in combination, and is not therefore limited to any particular configuration. For example, the ionic fluid may comprise at least one of plasma and an ionic liquid; the body may be configured as a hollow cylinder; the body may comprise a non-conductive material, and the non-conductive material may comprise at least one of glass and plastic; the acoustic transducer is coupled to a first end of the body, and the apparatus may include a second acoustic transducer coupled to a second end of the body that is opposite to the first end of the body; the second acoustic transducer may be coupled to the power supply; the apparatus may include a second power supply coupled to the second acoustic transducer that is configured to drive the second acoustic transducer in accordance with a second at least one frequency; the at least one frequency may be different from the second at least one frequency; the apparatus may include an electrode coupled to the acoustic transducer and the body, and a power source configured to produce radio frequency that is coupled to the electrode; the electrode may be configured to inject the radio frequency signal as a voltage varying with frequency into the ionic fluid when the ionic fluid antenna is operated in a transmit mode; the electrode may be configured to extract a voltage varying with frequency when the ionic fluid antenna is operated in a receive mode; the acoustic transducer may be included in a plurality of transducers arranged as part of a hexagonal geometry; adjacent pairs of the plurality of transducers may be configured to be driven in accordance with the at least one frequency; the apparatus may include a resonator coupled to the transducer, a resonator neck coupled to the resonator, and a conical coupler coupled to the neck, and the apparatus may include a tube, and an electrode coupled to the tube; the tube may have a length of approximately three-quarters of a wavelength associated with the operation of the apparatus, and the electrode may be separated from the transducer by approximately five-quarters of the wavelength; and the resonator may have a length that is approximately one-quarter of a wavelength associated with the operation of the apparatus.

Aspects of the disclosure are directed to an apparatus for providing an ionic fluid antenna used in secure communications, comprising: a body configured to contain an ionic fluid, an acoustic transducer coupled to the body, and a power supply coupled to the acoustic transducer that is configured to drive the acoustic transducer based on an encryption of data using polarized photons for quantum key distribution.

DETAILED DESCRIPTION

It is noted that various connections are set forth between elements in the following description and in the drawings (the contents of which are included in this disclosure by way of reference). It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may potentially incorporate one or more intervening entities.

In accordance with various aspects of the disclosure, apparatuses, systems and methods are described for an antenna, such as an ionic fluid antenna (IFA). For example, aspects of the disclosure are directed to an antenna that utilizes an ionic fluid with unique electrical properties as the radiating medium. Acoustophoresis may be leveraged to tailor the radio frequency (RF) conductivity of the ionic fluid. As used herein, acoustophoresis may refer to a change in density of a fluid subjected to sound waves. More generally, acoustophoresis may refer to a separation of particles using sound waves.

Referring now toFIG. 1, an IFA apparatus or structure100in accordance with one or more embodiments is shown. The structure100includes a body1configured to contain an ionic fluid. The ionic fluid may include a plasma or one or more ionic liquids. An ionic liquid may be used1fit has a conductivity greater than, e.g., 6 kiloSiemens per meter (kS/m). Simple solutions of salts, such as sodium chloride or copper sulphate can be used, either as aqueous solutions, or dissolved in another common solvent, such as ethylene glycol. Any salt with a low melting point (e.g. sodium aluminum tetrachloride, m.p. 185° C.), would provide an efficient radiating element.

The body1may be a hollow cylinder made out of one or more materials. Such materials may include glass, plastic, or any similar non-conductive material. The length of the body1can vary based on the application in which the structure100is used. For example, in a Wi-Fi application operating at a frequency of 2.4 GHz, the body1may include a cylinder of 31 mm in length (L) and 14 mm in diameter. The maximum diameter that is used or supported may be dependent on an applicable power limit. In an L-band Wi-Fi application operating at a frequency of 5.8 GHz, the body1may include a cylinder of 13 mm in length and 9 mm in diameter. The smaller size of the body1in the L-band Wi-Fi application is due to the shorter wavelengths of the transmitted radio waves of the L-band.

The body1need not be linear or rigid. However, maximizing the geometric symmetry of the body1may provide for the smallest possible gaps in terms of frequency band.

A first transducer2is located at one end of the body1and connects to an AC power supply3. A second transducer4is located at the second, opposite, or other end of the body1. The first transducer2and/or the second transducer4may be an acoustic transducer. In the embodiment ofFIG. 1, the second transducer4may be present and used to reduce the amount of power that is needed to drive the first transducer2.

In some embodiments, the second transducer4may be identical or substantially similar to the first transducer2. The second transducer4may share the power supply3with the first transducer2.

In some embodiments, the second transducer4may be driven by a separate AC power supply5that is different from the AC power supply3used to drive the first transducer2. Separate power supplies3,5may be used in embodiments where continuous wave tuning is provided. Continuous wave tuning may entail tuning with no loss of bandwidth due to gaps in frequencies. An acoustic frequency may be created parametrically, based on either a sum or difference of frequencies as described further below.

The structure100ofFIG. 1includes RF electrodes6and7located at opposite ends of the body1. The electrodes6and7may be used to couple the transducers2and4to the body1. A power source8that produces RF waves is coupled to the electrodes6and7via, e.g., coaxial cables.

As shown inFIG. 1, an RF wavelength (λRF) may be established that adheres to the formula:
λRF=c/vRF.

where c corresponds to the speed of light in the ionic fluid and vRFcorresponds to the frequency of the RF signal output by the power source8.

Also, as shown inFIG. 1, an acoustic distance or wavelength (λa) may be established for acoustic nodes present in the body1. The wavelength λaadheres to the formula:
λa=CS/fa,

where CScorresponds to the speed of sound in the ionic fluid and facorresponds to a frequency at which a transducer is driven. To the extent that more than one driving frequency is used (such as in embodiments where more than one transducer is used), the above formula may be modified accordingly.

The receiver circuit9and the T/R switch10may be used as part of a transmission or receive chain for communication purposes. The circuit9and switch10may be commercial off the shelf (COTS) products.

Referring now toFIG. 2, a plot200of efficiency of a resonant dipole antenna (along the vertical axis) as a function of the conductivity of the radiating medium used (along the horizontal axis) is shown. The efficiency of the resonant dipole antenna may vary in the same manner as an IFA. Accordingly, the concepts described below in connection with the plot200may be applied to an IFA or IFA structure, such as the structure100ofFIG. 1. As shown in the plot200, a small increase in conductivity (along the horizontal axis) may be reflected in a large increase in radiation efficiency of the antenna (along the vertical axis).

The plot200is subdivided into three distinct regions, denoted as Region1, Region2, and Region3. Region2is further subdivided into sub-region2aand sub-region2b. The ranges or demarcation points described below for the regions and sub-regions is illustrative; one skilled in the art would appreciate that the regions or sub-regions may be separated from one another at various other points or values of demarcation.

In Region1, the conductivity of the radiating medium is less than 3 kS/m. Region1represents a range of conductivity in which there are generally an insufficient number, amount, or concentration of mobile charge carriers available to support efficient radiation for the antenna element.

In Region2, which ranges from approximately 3 kS/m to 4.1 kS/m, the number of mobile charge carriers increases proportionately with the conductivity, resulting in a rapid increase in radiation efficiency.

In sub-region2a, the conductivity of the ionic fluid can be further increased by chemical doping. An example of chemical doping is provided by L. Zhou, “Porous Li4Ti5O1.2 Coated with N-Doped Carbon from Ionic Liquids for Li-Ion Batteries”, Advanced Materials, Volume 23, Issue 11, Pages 1385-1388, March 2011, which describes chemical doping by adding carbon to bi-metallic particles to enhance the conductivity of a lithium ion battery. These same particles can be used in liquid suspension for the IFA.

In sub-region2b, the RF conductivity can be increased over and above the increase achieved with chemical doping, by changing the density of the fluid using sound waves or acoustophoresis.

Region3represents antenna element conductivities above, e.g., 11 kS/m. In this region, there are an excess of mobile charge carriers, hence the efficiency of the antenna still increases, but much less rapidly than it does in Region2.

There are any number of ways an WA could be configured, dependent on the requirements of an application. Such requirements may include size, weight, and cost. In some embodiments, an WA is configured to use a single transducer, driven at a frequency of fa, to create a standing wave. The density of the charge carriers becomes more concentrated at the nodes of the standing wave, increasing conductivity of the ionic fluid. In a configuration employing two acoustic transducers, the first transducer (e.g., transducer2ofFIG. 1) is driven at an acoustic frequency of fa1, while the second acoustic transducer (e.g., transducer4ofFIG. 1) is driven at an acoustic frequency of fa2. The acoustic frequencies fa1and fa2combine to produce a standing wave of both the sum frequency:

(fa⁢⁢1+fa⁢⁢2)2
and the difference frequency:

The acoustic transducers (e.g., transducers2and4ofFIG. 1) and their associated driver circuits (e.g., power supplies3and5ofFIG. 1) can be commercially available, off-the-shelf (COTS). Using two transducers, the values of fa1and fa2may be predetermined. This increases the range of available frequencies many times over and above that produced by a single transducer.

The range of frequencies may be increased still further by using additional acoustic transducers in more complicated geometric configurations. For example,FIG. 3illustrates a portion of an WA apparatus or structure300arranged as a regular hexagonal geometry that utilizes a set of four transducers302a,302b,302c, and302d.

Assuming that adjacent pairs of acoustic transducers (e.g., transducers302aand302b) inFIG. 3were to be driven at a frequency of fa, then the acoustic resonances from those adjacent pairs of acoustic transducers may be equal to:
fasin(π/3).

Conversely, as shown inFIG. 3, if the adjacent pairs of acoustic transducers (e.g., transducers302aand302b) are driven at two different frequencies (e.g., fa1and fa2), then the number of resulting acoustic frequencies may include both the sum frequencies:

and the difference frequencies:

An IFA may be operated to create a radio frequency where a half-wavelength corresponds to the periodicity of the acoustic nodes. In a transmit mode of operation, the RF electrodes (e.g., electrodes6and7ofFIG. 1) inject the RF signal as a voltage varying with frequency vRFinto the ionic fluid. Similarly, in a receive mode of operation, a voltage varying with frequency vRFis extracted by the electrodes. Since the RF conductivity of the ionic fluid has been increased by acoustophoresis, the radiating efficiency of the fluid has correspondingly increased. In other words, a resonance condition is created between the RF signal and the acoustic wave. In the resonance condition:
vRF=cfa/2cs,

where vRFis the frequency of the RF signal, fais the superposition of fa1and fa2(as defined above), c is the speed of light in the ionic fluid, and csis the speed of sound in the ionic fluid. The frequency of the superimposed standing acoustic wave famay have a range of 5 kHz<fa<1 MHz, and the resulting RF (vRF) resonant frequencies may range from 665 MHz<vRF<130 GHz, which is a frequency range of about 200×. By comparison, a conventional broad band antenna, e.g., a log-periodic antenna, may at best have a frequency range of about 15×.

To illustratively demonstrate an increase in frequency range made possible by an IFA in accordance with the disclosure, an example of an IFA set up in a tube of length L (such as the structure100ofFIG. 1) may be considered. The spacing of the acoustic resonances in this example is given as Δfacs/2 L. The resonance conditions, which account for the high efficiency IFA, occur at spacings of ΔvRF=c/4 L.

In some embodiments, one or more control mechanisms may be connected to, or coupled to, an IFA structure (e.g., structure100or structure300). For example,FIG. 4illustrates a computing system400that may serve as a control mechanism. The system400includes one or more processors (generally shown by a processor402) and a memory404. The memory404may store data406and/or instructions408. The system400may include a computer-readable medium (CRM)410that may store some or all of the instructions408. The CRM410may include a transitory and/or non-transitory computer-readable medium.

The data406may include one or more parameters that may be associated with the operation of an IFA. For example, the parameters may include one or more of radiation patterns, directivity parameters, frequency parameters, frequency band parameters, gain parameters, polarization parameters, (effective) aperture parameters, etc. The data406may include signals or values associated with communication conducted using the IFA.

The instructions408, when executed by the processor402, may cause the system400to perform one or more methodological acts or processes, such as those described herein. As an example, execution of the instructions408may cause the system400to control the operation of an IFA.

Referring now toFIG. 5, a method500in accordance with one or more aspects of the disclosure is shown. The method500may be used to control the operation of an antenna, such as an IFA. The method500may be executed in conjunction with one or more systems, components, or devices. For example, the method500may be executed in conjunction with the system400, or a portion thereof.

In block502, a configuration for an IFA may be selected. The configuration may be selected based on the requirements of an application that is to be supported. As described above, the requirements may include a specification of size, weight, and cost. Other requirements may be taken into consideration as part of the selection of block502.

In block504, a control mechanism may be selected for controlling the operation of the IFA selected in block502. For example, one or more aspects of the system400may be selected or configured as part of block504, such as a specification of one or more parameters for operating the IFA.

In block506, the WA of block502and/or the control mechanism of block504may be constructed in accordance with the techniques described herein or using other techniques known to skilled artisans.

In block508, the constructed IFA and/or control mechanism of block506may be operated. The operation of block508may include the transmission or reception of one or more signals. The signals may be used to provide for communication between two or more parties or entities.

The method500is illustrative. In some embodiments, one or more blocks or operations of the method500, or one or more portions thereof, may be optional. The blocks or operations may executed in an order or sequence that is different from what is shown inFIG. 5. In some embodiments, one or more additional blocks or operations not shown may be included.

In some embodiments, the amplitude of a pressure wave in the fluid of an IFA can be increased by feeding an acoustic wave into the IFA tube via a resonant cavity. A resonant angular frequency ωHmay be expressed (potentially in terms of radians/second) as:
ωH=(A2P0γ/mV0)1/2,

where γ is the adiabatic index or ratio of specific heats, A is the cross-sectional area of the neck, m is the mass in the neck, P0is the static pressure in the cavity, and V0is the static volume of the cavity.

For cylindrical or rectangular necks:
A=Vn/Leq,

where Vnis the volume of the neck and Leqis the equivalent length of the neck with end correction and may be expressed as:
Leq=Ln+0.6DH,

where Ln is the physical length of the neck and DH is the hydraulic diameter of the neck. With the foregoing having been established, the resonant angular frequency OA may be expressed as:
ωH=(AVnP0γ/LeqmV0)1/2

Referring now toFIG. 6, a resonator feed600for an IFA in accordance with aspects of the disclosure is shown. The structure600may include a transducer602, such as for example a piezoelectric transducer coupled to a resonator (e.g., a quarter wavelength acoustic resonator as indicated by the arrow606). The structure600includes a resonator neck610(e.g., a wavelength resonator neck) and a conical coupler614(e.g., a wavelength conical coupler). From the coupler614the structure600transitions to a tube618. The tube618may be three-quarters of a wavelength in terms of length or dimension, at which point the structure600may transition to an electrode622. The electrode may be five-quarters (5/4) of a wavelength in terms of length or dimension from the transducer602.

The dimensions or lengths described above may be expressed in terms of an operating wavelength associated with the MA.

The IFAs described herein, and methods associated therewith, may provide for a number of features, including:

1) Tunability over ultra wide frequency bands, e.g., 500 MHz-130 GHz, which is a frequency range of approximately 200×. By comparison, the frequency range of a conventional log-periodic antenna is 500 MHz-7.5 GHz, or 15×.

2) Near-continuous tenability (Δv=100 MHz for a liquid antenna of length 50 cm), versus the large gaps (up to 10% of band of operation) of conventional log-periodic antennas, making the liquid antenna an ultra-efficient radiator.

3) Compact size (one-tenth the volume) relative to conventional antennas (such as a log-periodic antennas) that cover the same frequency band.

Any number of commercial applications may utilize or leverage the speed of the IFAs of this disclosure. As an example, sellers of stocks or equities may realize higher profit margins in connection with trading (e.g., high speed trading), potentially due to the (high) volume of trades involved. The IFAs of this disclosure represent a radical leap forward in antenna technology, with far-reaching implications for various networks, such as the Internet.

In accordance with aspects of the disclosure, an IFA may be used to provide secure communications. For example, the IFAs of this disclosure are suited for encryption using polarized photons for quantum key distribution, a highly secure and well-established technique. An extension to the use of quantum keys for standard encryption (e.g., 64 bit or 128 bit encryption) would be to establish a unique frequency scheduling table for two IFAS. The combination of a unique frequency scheduling table, or one-time pad, plus the IFA's unique ability to switch between frequencies, make it possible to send high speed messages at an unprecedented, unbreakable level of encryption—in fact, the absolute highest level of encryption possible. The frequency scheduling table may include a series of random frequencies that a pair of IFAs will exchange then switch between at predetermined time intervals.

Accordingly, the IFAs of this disclosure may be utilized in military applications, which demand the highest level of security possible. Absolute data security may be leveraged in hospital computer networks and other environments or applications where confidentiality of data is a concern. Any application on which the well-being of large numbers of people depends—communication networks, computer networks of power grids, etc. would be completely protected from the grave threat of cyber-terrorism.

Aspects of the disclosure have been described in terms of illustrative embodiments thereof. Numerous other embodiments, modifications, and variations within the scope and spirit of the appended claims will occur to persons of ordinary skill in the art from a review of this disclosure. For example, one of ordinary skill in the art will appreciate that the steps described in conjunction with the illustrative figures may be performed in other than the recited order, and that one or more steps illustrated may be optional in accordance with aspects of the disclosure.