Compensation method for the pattern of a planar printed inverted-f antenna

Abstract

The application discloses a planar printed inverted-F antenna pattern compensation method, and a plurality of metallized through holes are arranged on a medium substrate of the planar printed inverted-F antenna and connected with a metal floor to form a pattern compensation structure, so as to realize pattern compensation of the planar printed inverted-F antenna. By loading the metallized through holes, the current and electric field far away from the antenna are weakened, and the current on the floor is concentratedly distributed near the antenna, so that the floor integrity is ensured, the uncertainty in later processing is reduced, the radiation at ±60° is effectively reduced, and only one beam maximum value is ensured in the radiation pattern.

Description

Technical Field

[0001] This invention relates to the field of planar printed inverted-F antenna technology, and in particular to a method for pattern compensation of a planar printed inverted-F antenna. Background Technology

[0002] The inverted-F antenna can be seen as a modified structure evolved from a quarter-wavelength monopole antenna, with its length falling between one-quarter of the free-space wavelength and one-quarter of the dielectric waveguide wavelength. Planar inverted-F antennas (PIFA antennas) can be directly etched onto PCB substrates, offering advantages such as small size, strong anti-interference capability, easy fabrication, and flexible structure. However, for electrically small antennas like PIFAs, a finite ground plane can be considered part of the radiator, and its phase is synthesized with the antenna pattern, potentially distorting the radiation pattern into multiple beams. Different ground plane sizes affect antenna resonance and matching; the surface current and electric field of the ground plane significantly influence the radiation pattern. When the ground plane is relatively small compared to the antenna, the antenna radiation properties are good. However, when the ground plane is narrow and elongated, the maximum radiation direction is no longer the direction where Theta is 0°, but will be offset due to ground plane interference, even generating multiple maximum radiation beams; correspondingly, the gain in the Theta = 0° direction will also decrease. Summary of the Invention

[0003] The purpose of this invention is to address the technical deficiencies in the prior art by providing a pattern compensation method for a planar printed inverted-F antenna operating in the millimeter-wave band. By loading a metallized grounding via, the antenna pattern is corrected, reducing the influence of the narrow floor on the antenna radiation pattern, effectively offsetting the influence of the current and electric field generated by the floor on radiation, and correcting the pattern distortion caused by the floor's participation in radiation.

[0004] The technical solution adopted to achieve the purpose of this invention is:

[0005] A method for pattern compensation of a planar printed inverted-F antenna involves arranging several metallized vias that penetrate the dielectric substrate and are connected to a metal ground plane on the planar printed inverted-F antenna to form a pattern compensation structure, thereby achieving pattern compensation of the planar printed inverted-F antenna.

[0006] Preferably, the metallized via is arranged in the region outward at 1 / 4 wavelength of the PIFA receiving antenna and / or the PIFA transmitting antenna.

[0007] Preferably, the top end of the metallized through-hole is covered with a metal strip; the width of the metal strip is greater than the diameter of the metallized through-hole, and each metal strip is used to connect the metallized through-holes arranged in a straight line in the transverse and / or longitudinal direction at the top end and to separate adjacent metal strips.

[0008] Preferably, the spacing between adjacent metallized vias is the same or different.

[0009] Preferably, the diameters of the metallized through holes are the same.

[0010] Preferably, the metallized through-hole is a circular hole.

[0011] Preferably, the location of the metallized via is determined by the following method:

[0012] Through simulation, the radiation pattern of the planar printed inverted F antenna under a metal ground plane and dielectric substrate of specified size that meets the predetermined radiation requirements is found. Then, a radiation space that can form the radiation pattern is left on the dielectric substrate and metal ground plane, and the remaining space area is loaded with the metallized via to form a pattern compensation structure.

[0013] The radiation pattern compensation method for the planar printed inverted-F antenna of the present invention is applicable to situations in actual engineering where the ground plane is large and the integrity of the antenna ground plane needs to be maintained. The present invention weakens the current and electric field of the ground plane that are far from the antenna by using loaded metallized vias, so that the current on the ground plane is concentrated near the antenna. This not only ensures the integrity of the ground plane and reduces the uncertainty of subsequent processing, but also effectively reduces the radiation at ±60°, ensuring that there is only one beam maximum value in the radiation pattern. Attached Figure Description

[0014] Figure 1 A schematic diagram of a two-transmit, two-receive printed planar inverted-F antenna provided by the present invention;

[0015] Figure 2 A magnified 3D view of a partially enlarged inverted F-shaped printed planar antenna for two transmit and two receive antennas provided by the present invention (taking the F01 antenna as an example);

[0016] Figure 3a A 3D view of the two-transmitter, two-receiver inverted-F antenna structure with added pattern compensation provided by the present invention;

[0017] Figure 3b The top-level view of the two-transmitter, two-receiver inverted-F antenna structure with added pattern compensation provided by the present invention;

[0018] Figure 4 The surface current distribution of the ground plane of the dual-transmitter dual-receiver printed planar inverted-F antenna provided by the present invention (taking the excitation F01 antenna as an example);

[0019] Figure 5a The radiation pattern of the printed planar inverted-F antenna provided by the present invention at 24 GHz when excited by F01;

[0020] Figure 5b The radiation pattern of the printed planar inverted-F antenna provided by the present invention at 24 GHz when excited by F02;

[0021] Figure 5c The radiation pattern of the printed planar inverted-F antenna provided by the present invention at 24 GHz when excited by F03;

[0022] Figure 5d The radiation pattern of the printed planar inverted-F antenna provided by the present invention at 24 GHz when excitation F04 is applied;

[0023] Figure 6 The radiation pattern compensation for the inverted F antenna ground surface current distribution (taking the excitation F01 antenna as an example) is provided by the present invention.

[0024] Figure 7a The radiation pattern of the pattern-compensated inverted-F antenna provided by this invention is as follows: at 24 GHz, when excited by F01;

[0025] Figure 7b The radiation pattern of the pattern-compensated inverted-F antenna provided by this invention at 24 GHz when excited by F02;

[0026] Figure 7c The radiation pattern of the pattern-compensated inverted-F antenna provided by this invention at 24 GHz when excited by F03;

[0027] Figure 7d The radiation pattern of the pattern-compensated inverted-F antenna provided by this invention at 24 GHz when excited by F04;

[0028] Figure 8 A schematic diagram of the |S11| of two different inverted F antennas provided by the present invention (taking the F01 antenna as an example);

[0029] In the figure, 1 is the dielectric substrate (Rogers RO4350B), 2 is the metal ground plane on the lower surface of the dielectric substrate, F01-F04 are the numbers of the four PIFA antennas, where F01 and F02 are the first transmitting antenna and the second transmitting antenna, respectively, and F03 and F04 are the first receiving antenna and the second receiving antenna, respectively; 11, 12, and 13 are the feed stub, ground stub, and radiating stub of the inverted F antenna, respectively, which together form the inverted F antenna structure; A is the coaxial feed point, 14 is the short-circuit grounding metal hole; 5 is the metallized through-hole that penetrates the dielectric substrate and is connected to the metal ground plane. Detailed Implementation

[0030] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0031] The antenna in this embodiment of the invention is based on a MIMO (multiple-in multiple-out) system. MIMO systems place multiple antenna elements together at the transceiver end, utilizing spatial diversity or spatial multiplexing to increase the number of channels. This allows for doubling of channel capacity without increasing transmit power, improving transmission rates, overcoming multipath fading, and achieving high-quality communication. This MIMO system is frequently used in engineering for designing transceiver chips.

[0032] Figure 1 The diagram shows a two-transmit, two-receive printed planar inverted-F antenna without pattern compensation. F01 and F02 are the first and second transmitting antennas, respectively, and F03 and F04 are the first and second receiving antennas, respectively. Both the dielectric substrate and the metal ground plane are 65mm long and 3mm wide. To achieve directional radiation, the metal ground plane directly below the antennas is not removed. The four PIFA antennas are arranged as follows: the feed point must be designed according to the chip requirements; the first transmitting antenna F01 and the second transmitting antenna F02 are placed on the same horizontal line, with a horizontal spacing of 1 / 4 of the resonant wavelength; the first receiving antenna F03 and the second receiving antenna F04 are staggered, with both vertical and horizontal spacing of 1 / 4 of the resonant wavelength.

[0033] like Figure 2 As shown, the dual-transmitter, dual-receiver printed planar inverted-F antenna without pattern compensation has a 3mm width limitation, so the feed stub 11 is designed as a straight line. In the conventional planar printed inverted-F antenna provided by this invention, the antenna is coaxially fed at the coaxial feed point A, and the short-circuit grounding metal hole 4 penetrates the dielectric substrate to short-circuit the grounding stub 12, thus forming the basic structure of the inverted-F antenna.

[0034] During the design process, the length and width of the two stubs were calculated using formulas to ensure that the total length of the grounding stub 12 and the radiating stub 13 was 1 / 4 wavelength, enabling it to operate at 24 GHz. The impedance of this inverted-F antenna was adjusted by regulating the parameters of the feed stub 11 to regulate the distance from the coaxial feed point A to 13, as well as the widths of the feed stub 11, grounding stub 12, and radiating stub 13. The standard impedance value required for this type of inverted-F antenna meets engineering requirements. The substrate used is Rogers RO4350B, with a relative permittivity of 3.48.

[0035] Figure 1 and 2 The ground current distribution at the 24GHz resonant point of the two-transmit, two-receive printed planar inverted-F antenna with the unpattern-compensated structure shown is as follows. Figure 4 As shown, the current distribution on the floor surface without metal vias indicates that the floor also participates in radiation. Therefore, Figure 5a , Figure 5b , Figure 5c , Figure 5d The radiation pattern shown produces two maximum radiation beams at Theta = ±60°, while the radiation at Theta = 0° is relatively small, which will seriously affect signal reception and tracking.

[0036] Therefore, in practical implementation, simulation should be used to first determine the optimal radiation pattern of the antenna under the size of the metal ground plane and dielectric substrate. Then, optimal radiation space should be reserved on the dielectric substrate and metal ground plane, and the remaining space should be filled with uniformly arranged metallized vias (grounding vias). The spacing between the metallized vias is determined by the manufacturing precision. Figure 3a As shown. The processing requirement is that the top of the metallized through-hole should be covered by a metal strip. In this case, processing factors need to be considered to determine the width of the metal strip and the spacing between different metal strips, such as... Figure 3b As shown.

[0037] Figure 3a , 3b The image shows a two-transmit, two-receive printed planar inverted-F antenna with a pattern compensation structure, i.e., a printed planar inverted-F antenna structure with metal vias. Uniformly arranged metal vias with grounded bottoms are loaded on the substrate surrounding the antenna. The electric field at the metal vias is perpendicular to their surface, and the current and electric field distribution on the ground plane are significantly reduced. The ground plane current distribution at the 24GHz resonant point is shown below. Figure 6 As shown, the electric field at the via is perpendicular to its surface, and the current and electric field distribution on the floor are significantly weakened.

[0038] Figure 7a , Figure 7b , Figure 7c , Figure 7d The four radiation patterns obtained by exciting the four antennas after loading the radiation pattern compensation structure are shown. It can be seen that the radiation in the direction of Theta=±60° is significantly reduced and there are no longer multiple beam maxima.

[0039] The simulation results above show that the metal vias will reduce the radiation interference from the floor without affecting the radiation of the antenna itself, thus ensuring the antenna performance while giving the product better radiation performance.

[0040] Figure 1 and Figure 3a , 3b The S11 curves of the two printed planar inverted-F antennas shown are compared when excited by F01. Figure 8 As shown, in practice, the pattern compensation structure described in this invention will not have a significant impact on the impedance matching of the PIFA antenna.

[0041] In summary, metal vias will reduce radiated interference from the floor without affecting the antenna's own radiation, thus ensuring good radiation performance for the product while maintaining antenna performance.

[0042] In practical implementation, according to the principle of length contraction, if all the dimensions of the antenna are changed proportionally to the wavelength, the operating characteristics of the antenna will remain unchanged. Therefore, this method can be used to create antennas that operate at other frequencies with unchanged radiation patterns and impedance characteristics, and is not limited to 24GHz.

[0043] It should be noted that although the antenna in this embodiment of the invention is based on a MIMO system, it can be applied to PIFA antenna pattern compensation in other application scenarios and is not limited to MIMO systems.

[0044] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0045] Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A radiation pattern compensation method for a planar printed inverted-F antenna, characterized in that, A plurality of metallized vias penetrating the dielectric substrate and connected to a metal ground plane are arranged on the dielectric substrate of the planar printed inverted-F antenna to form a pattern compensation structure, thereby achieving pattern compensation for the planar printed inverted-F antenna; the metallized vias are arranged in the entire region outward from 1 / 4 wavelength of the PIFA receiving antenna and / or PIFA transmitting antenna; the top of the metallized vias is covered with a metal strip; the width of the metal strip is greater than the diameter of the metallized via, and each metal strip is used to connect multiple metallized vias arranged in a straight line at the top in the horizontal and / or vertical directions, and to separate adjacent metal strips; the first transmitting antenna F01 and the second transmitting antenna F02 are placed on the same horizontal line with a horizontal spacing of 1 / 4 resonant wavelength; the first receiving antenna F03 and the second receiving antenna F04 are placed alternately with a vertical spacing and a horizontal spacing of 1 / 4 resonant wavelength.

2. The radiation pattern compensation method for a planar printed inverted-F antenna according to claim 1, characterized in that, The spacing between adjacent metallized vias may be the same or different.

3. The radiation pattern compensation method for a planar printed inverted-F antenna according to claim 1, characterized in that, The diameters of the metallized through holes are the same.

4. The radiation pattern compensation method for a planar printed inverted-F antenna according to claim 1, characterized in that, The metallized through-hole is a circular hole.

5. The radiation pattern compensation method for a planar printed inverted-F antenna according to claim 1, characterized in that, The location of the metallized via is determined by the following method: Through simulation, the radiation pattern of the planar printed inverted F antenna under a metal ground plane and dielectric substrate of specified size that meets the predetermined radiation requirements is found. Then, a radiation space that can form the radiation pattern is left on the dielectric substrate and metal ground plane, and the remaining space area is loaded with the metallized via to form a pattern compensation structure.

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