JP2005516445A - DC induction short patch antenna - Google Patents

Abstract

  The DC induction short patch antenna (FIG. 2) includes a DC induction frequency selection surface (FIG. 1) forming a radiating element (306), a ground plane (202), a power feeding unit (314), a power feeding unit and a radiating element. And an RF portion (316) that is short-circuited to the ground plane located between the two.

Description

(Related application)
This application is filed with US provisional application serial no. A priority claim is made based on 60/354003 (filing date January 23, 2002). This application is named "Miniaturized PIFA (Miniaturized Reverse-Fed Planned Inverted-Fanten)" by Greg, S, Mendria and John, Dutton, William, Yee, Mackenzie III, and others. Provisional application serial No. 60/352113 (filing date January 23, 2002) and US provisional application serial no. 60/354697 (filing date Feb. 4, 2002). And these applications are hereby incorporated herein by reference in their entirety.

  In this application, the title of the invention is “LOW FREQUENCY ENHANCED FREQUENCY SELECTIVE SURFACE TECHNOLOGY AND APPLICATIONS”, and William, Yee, Mackenzie III, Greg, S, , Rodolfo, E, Diaz, US Provisional Application Serial No. 60/310655 (filed on August 6, 2001). This application is hereby incorporated by reference in its entirety.

  The present invention generally relates to antennas. In particular, the present invention relates to a reverse-fed planar inverted F-type antenna (PIFA).

  All generations of communication devices are designed to be physically smaller than previous generations. Small dimensions are preferred because they reduce physical dimensions and weight and improve user convenience.

  Many communication devices are designed and manufactured for consumer use. These include wireless devices such as cordless telephones, handy radios, personal portable information terminals and laptop computers. Like all consumer products, these wireless devices must be designed for low cost manufacturing and use.

  Manufacturers of wireless devices such as cordless telephones, personal portable information terminals and laptop computers have little room in products that are given cost-reducing pressures and extreme dimensions. All these devices require an antenna for wireless communication. Since these devices operate in various frequency bands, they often require multiple antennas. It is preferable to incorporate the antenna into a package or a case from the viewpoint of design, durability, and dimensions.

  In general, such wireless devices are packed with a significant amount of circuit wiring in a very small package. The circuit will include a logic circuit board and an RF circuit board. The printed circuit board can be thought of as a radio frequency (RF) ground to the antenna. And it is housed in a case that houses the circuit.

  In this way, a snugly stored antenna can be located very close to the ground plane without causing adverse effects such as frequency tuning drift, reduced frequency bandwidth and reduced efficiency. It can be used efficiently. The antenna solution should also be economical for use in consumer products.

  Various antennas with small contours have been developed. These include plate-like inverted F antennas (PIFA), short patch types, and various derivatives including serpentine lines. However, at present, none of these antennas meet the current design goals. The goal is to specify an antenna that is efficient, compact, and has a low attitude of λ / 60 maximum from the ground plane. Here, λ is a target frequency. Bluetooth standard with a maximum height of 2 to 3 mm from the ground plane, and therefore very suitable for devices that require the best performance in a compact volume, and also issued by the Bluetooth Special Interest Group (Bluetooth SIG) There is a specific requirement for 2.4 GHz antennas that operate according to (Bluetooth Standard) and IEEE Standard 802.11b issued by the Institute of Electrical and Electronics Engineers (IEEE).

Bluetooth standard equipment operates at 2.4 GHz (λ = 125 mm). Existing short patch antennas generally have a length of λ / 8 to λ / 4. An antenna useful for such an application should have a length on the order of λ / 10. One commercially available 2.4 GHz antenna is the Skycross model 222-0463, which can be purchased from Skycross. The volume of this antenna is 3300 mm ³ . The volume of the antenna useful for these applications is desirably 300 mm ³ or less.

  In addition to the small volume, portable devices are generally designed to be as light as possible. Commercially available surface mountable 2.4 GHz antennas are generally 5 g or more. Skycross model 222-0463 weighs 8.9 g. The weight of the antenna useful for these applications is desirably 1 g or less.

  As with all other equipment, the cost should be reduced. In published embodiments of small patch antennas, multiple metal layers and multiple vias are used to create a slow wavy line structure, such as a serpentine line. An example is shown in US Pat. No. 5,790,080. However, antennas useful for those applications only use one metal layer to make up the patch and do not use vias to reduce assembly costs.

  Designers also want all parts to be able to be mounted on the surface in order to reduce assembly costs. However, they also need low profile parts that fit within the usable volume. This problem is exacerbated when a ground plane is used under the generally desired surface mount antenna.

  Successful antennas need to be designed with the expectation to be surface mounted to the ground plane. A typical low profile 2.4 GHz antenna is Skycross Model 222-0463, which has a height of 3.56 mm. A lower height antenna is desired.

(Summary of Invention)
First, the present embodiment provides a direct current (DC) induction short patch antenna. In another embodiment, a direct current induction (DCL) frequency selection surface that includes a radiating element, a ground plane, a feed, and a radio frequency (RF) short located between the feed and the radiating element to the ground plane. An antenna including (FSS) is provided.

  Furthermore, other embodiments provide an antenna that is modeled by an equivalent circuit that includes a pair of connected feed lines. Each of the connection lines is defined by the even mode and odd mode intrinsic impedance and the even mode and odd mode effective dielectric constant.

  Yet another embodiment provides an antenna that includes a ground plane, a foam substrate disposed on the ground surface, and a polyimide layer disposed on the foam substrate.

  The antenna further includes a metal layer disposed on a polyimide layer that defines capacitance and inductance and causing resonance at one or more frequencies of interest.

  The above description of the preferred embodiment is merely an overview. The contents of this section do not limit the scope of the claims which define the scope of the invention.

(Detailed description of the invention)
This will be described with reference to the drawings. FIG. 1 is a diagram showing an equivalent circuit of a direct current inductive frequency selective surface (DCLFSS) structure.

  A direct current induction (DCL) frequency selection surface (FSS) is a surface on which conductors are periodically formed. It forms an inductor grid or grid 100 as shown in FIG. The illustrated example is a coplanar grid of wires that intersect at right angles. Each wire of the grid 100 can be modeled as an inductor 102 having a unique inductance. In addition, unit cells 104 are defined to make the model the required size with a suitable size.

  A more detailed model 106 is shown in FIG. In the model 106, a capacitor 108 is added in parallel to the inductor 102 to model the conditions in an actual embodiment of DCLFSS. Usually, there is a small amount of parasitic capacitance between the wires. And it serves to short the inductance.

  Furthermore, the unit cell 112 models the distribution of each wire throughout the DCL. The DCLFSS can be designed with this intended equivalent circuit, as well as an example of a uniplanar compact photonic bandgap (UC-PBG) structure. For example, Faye, Ran, Yang, and Kwang, Pin, Ma and Yong, Kwang and Tatsuo, and Ito's “Uniplanar Compact Photonic Bandgap Structure and Its Application” for Microwave Circuits) "(IEEE Transactions, Microwave Theory and Technology, Vol 47, No. 8, August 1999, pages 1509-1514). Additional background information examples include provisional application number 60/310655 (filing date: August 6, 2001), William, E, Mackenzie III and Greg, S, Mendria, Rodolfo, E, and Diaz. There is “Enhanced Frequency Selection Technology and Applications” (LOW FREQUENCY ENHANCED FREQUENCY SELECTIVE SURFACE TECHNOLOGY AND APPLICATIONS). This application is hereby incorporated by reference in its entirety.

  FIGS. 1A and 1B are isotropic surfaces where the values of L and C are uniform in both directions of the plane. And that means that such a surface will show the same frequency response for both horizontal and vertical polar electric fields.

  In the absence of a horizontal circuit, the frequency response is maintained only for vertical field polarity and the FSS is said to be anisotropic. However, a more complex type of anisotropy is shown in FIG. Here, the meander line 114 of the unit cell 116 is formed.

  By the way, if the ground plane is located near this finite meandering line 114, the structure supports even and odd modes associated with a connecting line that will become a dual band antenna when input normally. will do. In the presently disclosed embodiment, a one-turn meander line of a DCL circuit is used.

  The present embodiment relates to a miniaturized dual band patch antenna. In the first embodiment, the antenna is defined by several characteristic equipments. As an example, in the first embodiment, only one metal layer is used to form a patch. The preferred embodiment is a one-turn meander line with two very close connection lines.

  Since the power supply post and the ground post retain the conventional shorted patch design, the power supply post is located at the corner of the patch. The single layer of metal that forms the patch incorporates an inductor and a capacitor in parallel, and when connected as an infinite periodic structure, behaves as a direct current induced frequency selection surface.

  The wiring pattern around the antenna of the first embodiment has a width at least twice the width of the inner wiring pattern in the DCLFSS unit cell. This has been shown to significantly increase radiation efficiency.

  FIG. 2 is a view showing a photograph of the first embodiment of the DCLFSS short patch antenna 200. The antenna 200 includes a ground plane 202, a dielectric layer 204, a polyimide layer 206, and a metal coating 208. Any suitable manufacturing method may be used for manufacturing the antenna 200. The dimensions may also vary from those shown in FIG. 2 depending on physical requirements and performance.

  As an example, the antenna 200 generally has a rectangular shape. This rectangle may vary in shape factor and aspect ratio that would be required in a particular implementation to follow performance requirements.

  The antenna 200 shown in FIG. 2 has a metallization 208 of the pattern shown in FIG. 2 printed on a polyimide layer 206 having a thickness of 1 mm, and the polyimide layer 206 has a foam forming dielectric thickness of 2.0 mm. Produced by adhering layer 204.

  The antenna 200 as a whole occupies an outer shape of 8.6 mm × 12.5 mm × 2.2 mm. Polyimide can be bonded to the foamed resin using an inexpensive pressure sensitive adhesive. Thereafter, the antenna 200 is attached to a corner of the FR4 ground plane 202 having a general size of 45 mm × 45 mm.

  FIG. 3 is a front view of the antenna 200 of FIG. FIG. 3 is a diagram showing a DCL short patch pattern used for the antenna 200. In FIG. 3, a green region 302 is a conductor, and a yellow region 304 is a flexible substrate such as polyimide.

  In order to operate as a short patch antenna or a plate-like inverted F antenna (PIFA), the metal coating 208 forms a radiating element 306. The radiating element 306 includes a radiating unit 308, a feeding end 310, and a ground point 312. The antenna 200 includes a feed pin 314 and an RF short pin 316.

  In the illustrated embodiment, the RF short pin 316 is located between the feed pin 314 and the ground point 312. This is the reverse-feeding of the antenna 200. This is a provisional patent application filed on the same day by Greg, S, Mendolia and John, Dutton, William, Yi, and Mackenzie III ”In more detail. This application is hereby incorporated by reference in its entirety.

  In other embodiments, more common power feeding techniques are used. Here, the feed 314 is located between the RF short 316 and the radiating portion 308.

  As shown in FIG. 2, the power supply pin is a printed metal wiring formed by etching on a flexible polyimide substrate. However, it can be replaced with any similar length-width ratio conductive structure such as metal pins, posts, straps, rods, screws, wires, rivets and the like. The same is true for RF short pins.

  The embodiment of FIG. 3 also includes both an interdigitated portion, such as the interdigitated portion 320, and one or more serpentine portions, such as a serpentine portion 322. In the interdigitated portion, the plurality of finger-like portions of the metal film short-circuited at one end are located in the vicinity of the other finger-like portions short-circuited at one end. In the meandering portion, a plurality of turning portions on the same line of the metal coating are arranged close to each other. Both the interdigitated portion and the serpentine portion are useful for adjusting the capacitance and inductance of the DCLFSS.

  As can be seen from FIG. 3, both techniques have been used repeatedly in antenna 200 to achieve a desired performance goal. Unit cell 324 includes a lowermost alternate fitting portion, a meandering portion thereon, and an alternate fitting portion above the meandering portion. The patch is an array of such unit cells 324, in which two unit cells are arranged in the width direction and three unit cells are arranged in the height direction.

  The illustrated embodiment is merely exemplary. Other types of unit cells and configurations can also be selected. Other format choices will depend on availability, performance and cost requirements. The design will also be selected experimentally by simulation and analytical evaluation.

  Throughout the antenna 200, the line width and spacing will be selected according to design rules and performance goals. In the embodiment of FIG. 3, most of the line width and spacing are set to 0.2 mm.

  Along the four vertical wirings and one horizontal wiring on the outer periphery of the antenna 200, the line width is set to 0.4 mm. The use of wider 0.4 mm wide wiring around the unit cell is preferred for some applications. This is because they have been found to improve the radiation efficiency of the DCL short patch antenna compared to using a uniform 0.2 mm wire.

  The overall size of the upper surface of the antenna 200 is 8.6 mm × 12.4 mm.

  In order to improve the antenna efficiency of the DCL short patch antenna shown in FIG. 3, the widths of the peripheral wirings 302 and 306 may be increased in the same manner as the wiring width along the upper peripheral part. And it shorts two pairs of DCL transmission lines.

  These wirings can be increased to a few mm (λ / 40) without a significant effect on the resonant frequency of the antenna. It is also possible to improve the efficiency of the antenna by increasing the thickness of the metal coating.

  FIG. 4 is a diagram showing the return loss of the antenna 200 of FIGS. This antenna is clearly resonating at two subharmonic frequencies near 2460 MHz and 5330 Mhz. This measurement was performed using an antenna 200 mounted on a corner of a 45 mm square ground plane.

  Thus, the antenna 200 is well suited for Bluetooth frequency band addresses from 2.400 GHz to 2.49 GHz, as well as the 802.11 wireless local area network (WLAN) frequency band near 5.1-5.3 GHz. Is.

  In the test measurement of the manufactured antenna, the radiation efficiency of the preferred embodiment was generally 73% in the low frequency band (2460 MHz) when mounted on the corner of a 45 mm square ground plane.

  As a test measurement method, a 3.5-inch square waveguide-shaped wheeler cap test facility was adopted. A 7.5 inch square ground plane is formed at the bottom of the wheeler cap, and this larger ground plane is electrically connected to the 45 mm square ground plane via an SMA barrel connector.

  This same antenna and ground plane measurement set up in the antenna test chamber showed a maximum radiation efficiency of 72%. This is consistent with within 0.03 dB. These measured efficiencies include the 0-0.2 dB line loss of the test equipment 2-inch coaxial cable. Therefore, the actual antenna efficiency is approximately 75%.

  The DCL short patch antenna 200 is modeled using a full frequency simulation tool.

  FIG. 5 is a diagram showing a computer model used in this simulation. FIG. 5 (a) is an isometric view of the simulated antenna. FIG. 5B is a front view of the simulated antenna. FIG. 5C is a cross-sectional view of the simulated antenna.

  This model is almost the same as the embodiment of FIGS. The difference is that the line width around the antenna is smaller, 0.2 mm, and the RF short is located about twice the distance from the power supply.

  The simulated antenna is zero thickness, has a very small ground plane of 10 × 14 mm, and is excited by a series voltage source located at the base of the wire forming the feed post. This power source also has a power impedance of 50Ω.

  FIG. 5 specifies other simulation conditions including a foam dielectric with a bottom area of 7.8 mm × 12 mm, a thickness of 1.95 mm, and εr = 1.2. The polyimide layer has a bottom area of 7.8 mm × 12 mm, a thickness of 0.05 mm, and εr = 3.3. The metal patch is zero thickness copper. The power feeding unit is a wire having a radius of 0.02 mm, and is located at coordinates x = 7.7 mm and y = 0.1 mm. The RF short is a wire having a radius of 0.05 mm and is located at coordinates x = 7.7 mm and y = 4.1 mm.

  Dual band operation is demonstrated in simulations with resonances around 2.27 GHz and 4.83 GHz with a ratio of 2.13. The three-dimensional radiation pattern included in the attached file indicates that the main polarization is clockwise circular polarization in the low frequency band and counterclockwise circular polarization in the high frequency band.

  FIG. 6 is a diagram showing a surface current at a resonance frequency (2.27 GHz) in a low frequency band. The instantaneous current is plotted for a specific time phase from ωt to 30 °. The series voltage power supply used in the simulation has a phase angle of 0 °.

  Each figure in FIG. 6 is a diagram showing different maximum values for the color spectrum to reveal details in a still image. FIG. 6A is a diagram showing a maximum surface current of 60 A / m as follows. FIG. 6B is a diagram showing a maximum surface current of 30 A / m. FIG. 6C is a diagram showing a maximum surface current of 15 A / m.

  FIG. 6 is a diagram showing the maximum current in the periphery of the unit cell. Therefore, the four vertical wires are intentionally manufactured to have twice the width of all the internal wires, reducing the current density in those wires. This change results in improving the radiation efficiency measured by the Wheeler cap test from the middle 50% range to the lower 70% range. This is a significant improvement in efficiency for all antennas.

  FIG. 7 is another diagram illustrating the surface and wire currents of the simulated antenna of FIG. FIG. 7 reveals that the total current in the short post or short wire greatly exceeds the current in the feed post.

  This is a US Provisional Application No. 60/352113 filed by Greg, Es, Mendria and John, Dutton and William, Yee, Mackenzie III, and will receive more detailed information (filing date January 23, 2002). ) And US Provisional Application No. 60/354597 (Filing Date February 4, 2002) is also the most important part of the "miniaturized PIFA (MINIATURIZED REVERSE-FED PLANAR INVERTED-F ANTENNA)".

  Another conclusion can be obtained from the simulation results of FIG. First, a relatively low current density was observed inside the unit cell. Secondly, as can be seen from FIG. 6 (a), the highest current density on the patch was observed at the bridge portion at the center of the upper end, where the two pairs of power transmission lines are joined.

  FIG. 8 is a diagram showing an equivalent circuit 800 in which the DCLFSS short patch antenna is basically modeled as a pair of connected power transmission lines.

  The equivalent circuit 800 includes a first power transmission line 802 having a first segment 804 and a second segment 806. Similarly, equivalent circuit 800 includes a second power transmission line 808 having a first segment 810 and a second segment 812. The feeding point 814 is located at one end of the first segment 804 of the first power transmission line 802. The RF short 816 is located at a circuit node portion that separates the first segment 804 from the second segment 806.

The connected power transmission lines are uniquely defined by their even mode intrinsic impedance Z _oe and their odd mode intrinsic impedance Z _oo . This is similar to the case where the effective dielectric constant is defined by the even mode ε _e and the odd mode ε _o .

  One benefit of a DCL patch using a regular integrated link transmission line, as illustrated here, as compared to an integrated patch is that the effective dielectric constant of the DCL patch increases by more than 1. It is. This slows down the phase velocities of both even and odd modes on the connection line, allowing a more compact antenna design. This can be easily achieved by patterning the feed line including the DC conductive unit cell, as shown in the example of FIG. 2, without adding the cost and weight of any dielectric load material.

As a circuit model for comparison with measured data, the equivalent circuit 800 of FIG. 8 was modeled using various circuit models assuming the following values: Z _oo = 50Ω, Z _oe = 100Ω, ε _e = ε _o = 1.5, Len ₁ = 4 mm, Len ₂ = 8 mm, C ₁ = C ₂ = 0.25 pF, C ₃ = 0.47 pF, L ₁ = L ₂ = 0.5 nH, R ₁ = 3000Ω , R ₂ = 1500Ω.

  FIG. 9 illustrates the simulation result. The above measurements associated with FIG. 4 show 2460 MHz and 5330 MHz, whereas the model predicts resonant frequencies of 2487 MHz and 5262 MHz and a ratio of 2.12.

  The proposed circuit model 800 of FIG. 8 builds on past experience with the simpler patch antenna being modeled.

L ₁ and L ₂ represent the parasitic inductances of the feed post and the short post, respectively. Lumped capacitances C ₁ , C ₂ , C ₃ model the peripheral area at one end of the connecting lines 802 and 808. These capacitive loads are also known as radiation susceptance, and there are standard equations for predicting these values.

The concentrated resistances R ₁ and R ₂ are models of radiation loss or radiation conductance. The most difficult parameter to estimate is the connected transmission line parameter. However, they can be estimated by experimental means. The advantage of such a model is that consideration of circuit model parameters can provide perspective and design guidance.

From the above, the disclosed embodiment provides an antenna that satisfies the size, weight, cost, and surface mount requirement specifications described above. This antenna of one embodiment has a maximum linear distance of only λ / 10 at frequencies below the two resonant frequencies. Volume is about 0.00011λ ^3. This is a volume that is smaller than an order of magnitude compared to an antenna of a type that is directly mounted on a ground plane currently on the market.

  The absence of dielectric material other than the thin polyimide used to support the printed wiring allows the antenna of this embodiment for a 2.4 GHz antenna to weigh on the order of 0.25 g or less. It can be made at least 50 times lighter than a commercially available antenna.

  The illustrated embodiment has a vertical height from the ground plane of approximately λ / 60, and other heights are possible in other embodiments. Even a recent commercially available meander line antenna has a minimum height of λ / 35.

  From hardware experiments, it has been found that the DCL short patch shown here does not easily detune due to changes in the size of the ground plane and proximity of the dielectric. The antenna according to the present embodiment resonates with a sufficient VSWR bandwidth that can be used in a multi-frequency band such as a Bluetooth frequency near 2.4 GHz or 5.2 GHz or a frequency of IEEE standard 802.11.

  Several physical features are combined to achieve a low cost manufacturing method. First, it has a small footprint, second, only a single layer of patch metal is required, and third, the design is powered from the periphery and grounded, so no feed pins are required, Fourth, the feature is that a new kind of material is not required.

  These features are suitable for application to wireless devices such as a wireless communication device, a PDA, a laptop computer connected to a wireless LAN, and a personal area network (PAN). The technology can be scaled to various frequencies.

  For example, 800 MHz (mobile phone), 900 MHz (GSM), 1500 MHz (GPS), 1800 MHz (GSM), 1900 MHz (PCS), 2400 MHz (Bluetooth, IEEE standard 802.11), 5200 MHz (IEEE standard 802.11), and more For example, high frequency.

  There are other embodiments of DCL short patch antennas. However, the performance of such an embodiment may vary from the performance of the design described above.

  FIG. 10 is one such embodiment of a DCL short patch 1000. The illustrated embodiment of the short patch 1000 of FIG. 10 is simpler than the previously described embodiment. This is because the patch 1000 is basically formed of uniform unit cells 1002 and has no connection line.

  The DCL patch 1000 is short-circuited at one end 1004 like a conventional PIFA. The DCL patch 1000 is fed at a substantially central feeding point 1006 below the patch 1000 as shown in FIG. This is the same as the conventional PIFA. As in the conventional PIFA, the ground point 1008 is located approximately at the end 1004 of the patch 1000.

  FIG. 11 is a diagram illustrating two photographs of one embodiment of a DCL patch 1100. FIG. 11A is a front view of the front side of the patch 1100. FIG. 11B is an isometric view of the patch 1100 on the ground plane side.

  In this embodiment, the front side 1108 is fabricated on a double-sided 0.062 inch FR4 using an 8 mil (about 0.2032 mm) line and an 8 mil (about 0.2032 mm) gap for DCLFSS. The SMA connector 1102 is soldered to the ground plane side 1104 of FR4.

  The central coaxial conductor 1106 extends as a feeding probe via FR4 to excite DCLFSS. The feed pin 1110 and the RF short pin 1112 are soldered wires.

  FIG. 12 is a diagram illustrating the return loss of the embodiment of the DCL patch 1100 of FIG. A dual band response can be recognized showing resonance frequencies around 2.0 GHz and 2.82 GHz. Note that the ratio between the resonant frequencies in this example is only 1.41: 1.

  The above two examples show that the DCLFSS material can also be used as a patch antenna in which DCLFSS is anisotropic. In other words, the patch currents in the x and y directions show different sheet impedances or different equivalent circuits. The patch current is the current in the metal or other conductor on the surface of the patch.

  In this example, the x and y axes are orthogonal and in the FSS plane. A good example is shown here, but there are many physical implementations of anisotropic DCLFSS materials. However, it is possible and probably desirable to produce a DCL short patch antenna using isotropic DCLFSS.

  FIG. 13 is a diagram illustrating one embodiment of an isotropic DCL short patch 1300. In the patch 1300, a uniplanar compact photonic bandgap (UC-PBG) structure is used for the patch. This FSS pattern is also known as a crossed Jerusalem groove array. The unit cell of the UC-PBG structure is clarified in FIG.

  As FSS, the equivalent circuit of the patch 1300 is estimated by the circuit shown in FIG. The unit cells of patch 1300 are separated by a trace 1304 forming an inductor and a gap 1302 forming a capacitor, as modeled by the equivalent circuit of FIG.

  In this antenna example, the capacitor gaps 1302 between unit cells are the same size in both orthogonal directions, such as inductor traces or insertion gaps 1306 that define their outline. This symmetry produces an isotropic DCLFSS. However, the LC value can be made anisotropic by independently changing the shape in the x and y directions.

  An important point for understanding the DCL short patch antenna is that the DCLFSS unit cell is very small for the free space wavelengths of all antenna resonant frequencies. The standard unit cell dimensions of the first two embodiments are 2-4% of the free space wavelength of the lowest resonant frequency. Other dimensions can be used as well.

  In FIG. 13, points indicated by “A” and “B” are the positions of the feeding point and the RF short point, respectively. A conventional feeding point is point B. The reverse power supply PIFA uses point A as a power supply point.

  A variation of the embodiment of FIG. 13 provides a higher performance, serpentine line DCL short patch antenna 1400 of FIG. The antenna 1400 is obtained with a simply cut selected y-direction inductor trace. As an example, traces 1402 and 1404 have been cut compared to the embodiment of FIG. Traces 1406 and 1408 remain intact and form a serpentine line. Here, in the case of 90 ° rotation, the DC induction path meanders to the left and right, and therefore, an equivalent circuit of DCLFSS can be modeled similarly to the embodiment of FIG.

  While characteristic embodiments of the present invention have been shown and described, various modifications can be made. Accordingly, the claims are intended to cover such changes and modifications as fall within the true spirit and scope of this invention.

FIG. 1 is a diagram showing an equivalent circuit of a direct current induction (DCL) frequency selection plane. FIG. 2 is a photograph of one embodiment of a DCL short patch antenna. FIG. 3 is a plan view of the DCL short patch antenna of FIG. FIG. 4 is a diagram showing the results of measuring the return loss of the DCL short patch antenna of FIGS. 2 and 3. FIG. 5 is a diagram showing a full radio wave simulation model of the DCL short patch antenna. FIG. 6 is a diagram showing the current at the moment of simulation calculated using the simulation model of FIG. FIG. 7 is a diagram showing a result of all radio waves simulation of the DCL short patch antenna. FIG. 8 is a diagram showing a distributed equivalent circuit model of the DCL short patch antenna. FIG. 9 is a diagram showing an expected return loss of the model of FIG. FIG. 10 is a diagram showing a second embodiment of the DCL short patch antenna. FIG. 11 is a diagram showing a photograph of the design of the antenna of FIG. FIG. 12 is a diagram showing the results of measuring the return loss of the DCL short patch antenna described in FIGS. 10 and 11. FIG. 13 is a diagram showing a DCL short patch using an isotropic DCL FSS. FIG. 14 shows a meandering line DCL short patch antenna.

Claims (20)

A direct current induction (DCL) frequency selective surface (FSS) having a radiating element;
The ground plane,
A power feeding unit;
A radio frequency (RF) short to the ground plane;
A patch antenna characterized by comprising: The patch antenna according to claim 1, wherein the power feeding unit is located substantially at a corner of the patch antenna. The patch antenna according to claim 1, wherein the power feeding unit is located at one end of a power transmission line forming the radiating element. 2. The patch antenna according to claim 1, wherein the RF short is at a position where a distance from the RF short to the center of the patch antenna is smaller than a distance from the power feeding unit to the center of the patch antenna. The patch antenna according to claim 1, wherein the patch antenna is manufactured as a pair of connected power transmission lines. The DCLFSS has a metal coating disposed on a dielectric layer;
The patch antenna according to claim 1, wherein the metal coating is separated from the ground plane by the dielectric layer. The patch antenna of claim 1, wherein the metal coating is patterned to define capacitance and inductance of the DCLFSS. 8. The patch antenna of claim 7, wherein the metal coating is patterned to define one or more interdigitated portions. The patch antenna of claim 7, wherein the metal coating is patterned to define one or more meanders. 8. The patch antenna according to claim 7, wherein the metal coating is patterned to define a combination of one or more interdigitated portions and one or more meandering portions. The metal coating comprises a surrounding metal line having a first width;
A patterned metal line having a second width and at least partially inside the surrounding metal line;
The patch antenna according to claim 7, further comprising: Having a pair of connected power transmission line parts, each defined by an even mode and an odd mode specific impedance, and an even mode and an odd mode dielectric constant;
An antenna modeled by an equivalent circuit characterized in that the effective dielectric constant exceeds 1 by using printed inductors and printed capacitors instead of using medium to high dielectric constant substrate material. The antenna according to claim 12, wherein the power feeding unit is located substantially at a terminal end of one of the connected power transmission line units. The antenna according to claim 12, wherein an RF short to the ground is located at a circuit node portion between the connected power transmission line portions. The ground plane,
A foam substrate;
A flexible dielectric layer disposed on the foam substrate;
A metal coating disposed on the flexible dielectric layer that defines capacitance and inductance and causes resonance at one or more frequencies of interest;
An antenna comprising: The antenna of claim 15, wherein the metal coating is patterned to define a radiating element including a feed end and a radiating portion. A power supply unit electrically connected to the power supply end of the radiating element;
An RF short section disposed to be electrically grounded to a ground point of the radiating element located between the feeding end and the radiating section;
The antenna according to claim 16, further comprising: The antenna according to claim 15, wherein the metal coating has one or more meandering lines. The antenna according to claim 15, wherein the metal coating has one or more alternating fitting structures. The metal coating has one or more interdigitated structures combined with one or more serpentine lines;
Resonance occurs at one or more frequencies of interest,
The antenna according to claim 15.

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