A PIFA antenna array and radio frequency antenna system

Abstract

The present application belongs to the field of antenna technology and provides a PIFA antenna array and a radio frequency antenna system. The PIFA antenna array includes: a first grounding ring structure, a first antenna, a second grounding ring structure, a second antenna and an isolation ring structure. The first end of the first antenna is connected to a ground plate through the first grounding ring structure, and the second end is open. The signal feeding point of the first antenna is arranged between the first end and the second end thereof; the first end of the second antenna is connected to the ground plate through the second grounding ring structure, and the second end is open. The signal feeding point of the second antenna is arranged between the first end and the second end thereof. The isolation ring structure is arranged between the first antenna and the second antenna. The first side surface of the isolation ring structure is connected to the first grounding ring structure, the second side surface opposite to the first side surface is connected to the second grounding ring structure, and the third side surface is connected to the ground plate, thereby providing a new type of PIFA antenna array, which makes the built-in antenna light, thin and small without reducing the antenna performance.

Description

Technical Field

[0001] The present application relates to the field of antenna technology, and in particular to a PIFA antenna array and a radio frequency antenna system. Background Art

[0002] Now with the rapid development of mobile communications and the improvement of people's material living standards, handheld mobile communication devices have become an indispensable tool in daily life. The penetration rate of various mobile terminal devices in society is increasing very fast, and based on the national policy background of encouraging the development of the communications industry in the new infrastructure, WIFI6 and 5G will be a huge market with great development space in the future. The ultra-wideband backbone network brings rich network information resources. Through this high-speed broadband network, various personal demand information can be established, and various enterprises can also realize new market forms such as remote control through the network. Among them, the most convenient and fastest way of communication is wireless access, because wireless access saves a lot of network laying costs, easily realizes flexible access anytime, anywhere, and maintenance is relatively simple. For example, the latest WIFI6 technology is an ultra-high-speed ultra-wideband communication technology. This technology uses the MIMO working mode of multiple antennas and multiple ports, and also has multi-band system technology, which can easily reach a working rate of 5400Mbps.

[0003] However, the development of new technologies also brings new problems, because the increase in speed requires a rapid increase in the number of antennas, but the internal space of the product is getting smaller and smaller. How to achieve the coexistence of a large number of antennas in a small space, and ensure that each antenna plays its intended role? In order to meet this new harsh reality, the corresponding multi-antenna close-range decoupling technology came into being. Most of the current built-in antennas use the inverted F antenna (PIFA) topology. However, the inverted F antenna has a fatal flaw. The radiation efficiency of the entire antenna is greatly affected by the ground size and shape of the motherboard PCB. Two or more PIFAs placed on the same PCB will cause serious mutual interference. Therefore, conventional PIFA antennas are basically single-antenna applications. At most, two PIFA antennas can be arranged diagonally at a long distance. The spacing must generally reach a distance of 10 wavelengths to approximately achieve a long-distance ground current zeroing state.

[0004] Generally, the antenna is required to have good impedance matching characteristics, stable radiation directivity, relatively flat gain characteristics and polarization characteristics within its operating frequency band, and it is hoped that the antenna is small enough, low cost, and easy to process and install. At present, the built-in PCB printed antennas of various network communication terminal products are developing in the direction of small space and high performance. How to design a miniaturized built-in antenna has become a difficulty and bottleneck in the development of mobile communications. Summary of the invention

[0005] The purpose of the present application is to provide a PIFA antenna array and a radio frequency antenna system, aiming to provide a miniaturized built-in antenna without reducing the antenna performance.

[0006] In a first aspect, the present application provides a PIFA antenna array, comprising:

[0007] a first grounded ring structure;

[0008] a first antenna, wherein a first end of the first antenna is connected to a ground plate through the first grounding ring structure, a second end of the first antenna is open, and a signal feeding point of the first antenna is arranged between the first end of the first antenna and the second end of the first antenna;

[0009] a second grounded ring structure;

[0010] a second antenna, wherein a first end of the second antenna is connected to the ground plate through the second grounding ring structure, a second end of the second antenna is open, and a signal feeding point of the second antenna is arranged between the first end of the second antenna and the second end of the second antenna;

[0011] An isolation ring structure is arranged between the first antenna and the second antenna, the first side of the isolation ring structure is connected to the first grounding ring structure, the second side of the isolation ring structure is connected to the second grounding ring structure, and the third side of the isolation ring structure is connected to the ground plate.

[0012] Optionally, the first grounding ring structure and the second grounding ring structure are both hollow ring structures.

[0013] Optionally, the first grounding ring structure is perpendicular to the isolation ring structure.

[0014] Optionally, the total length of the first grounding ring structure is 0.43λ, where λ is a wavelength.

[0015] Optionally, the total length of the sides of the isolation annular structure is 0.5λ, where λ is the wavelength.

[0016] Optionally, the isolation annular structure is a hollow structure.

[0017] Optionally, the first antenna is a single radiating element.

[0018] Optionally, the length from the signal feeding point of the single radiating oscillator to the second end of the single radiating oscillator is 0.2λ, where λ is the wavelength.

[0019] Optionally, the length from the signal feeding point of the single radiating oscillator to the first end of the single radiating oscillator is 0.18λ, where λ is the wavelength.

[0020] A second aspect of the present application further provides a radio frequency antenna system, comprising a PIFA antenna array as described in any one of the above items.

[0021] In the PIFA antenna array and radio frequency antenna system provided by the present application, the PIFA antenna array includes: a first grounding ring structure, a first antenna, a second grounding ring structure, a second antenna and an isolation ring structure, wherein the first end of the first antenna is connected to the ground plate through the first grounding ring structure, the second end of the first antenna is open, and the signal feeding point of the first antenna is arranged between the first end of the first antenna and the second end of the first antenna; the first end of the second antenna is connected to the ground plate through the second grounding ring structure, the second end of the second antenna is open, and the signal feeding point of the second antenna is arranged between the first end of the second antenna and the second end of the second antenna, the isolation ring structure is arranged between the first antenna and the second antenna, the first side surface of the isolation ring structure is connected to the first grounding ring structure, the second side surface of the isolation ring structure is connected to the second grounding ring structure, the third side surface of the isolation ring structure is connected to the ground plate, and the first side surface of the isolation ring structure and the second side surface of the isolation ring structure are arranged opposite to each other, thereby providing a new type of PIFA antenna array, which makes the built-in antenna light, thin and small without reducing the antenna performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the inverted-F antenna structure in the prior art.

[0023] Figure 2 It is a schematic diagram of the PIFA antenna array structure of the present invention. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application.

[0025] The term "comprising" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method or system, product or device comprising a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. In addition, the terms "first", "second" and "third" etc. are used to distinguish different objects, rather than to describe a specific order.

[0026] It should be noted that when a component is referred to as being "fixed on" or "disposed on" another component, it may be directly or indirectly located on the other component. When a component is referred to as being "connected to" another component, it may be directly or indirectly connected to the other component. The orientation or position indicated by the terms "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. is based on the orientation or position shown in the accompanying drawings, and is only for the convenience of description and cannot be understood as a limitation on the present technical solution. In addition, the terms "first", "second" and "third" etc. are used to distinguish different objects, rather than to describe a specific order, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0027] Conventional single-body inverted F antenna (PIFA) has the unique advantages of simple structure, light weight, conformal, low manufacturing cost, high radiation efficiency, easy to achieve multi-band operation, etc. This type of antenna has a low profile structure, and the radiation field has two polarizations, horizontal and vertical. In addition, due to its compact structure and isotropic radiation characteristics, the flexible adjustment of its grounding design point can effectively improve the impedance matching state of the antenna. Figure 1 The figure shows a typical inverted F antenna structure. This antenna can be regarded as a resonator with a short circuit at the e end and an open circuit at the a end. Ground is the ground plane, the c end is the feed point, the b end is the common connection point of the feed point c and the open circuit end a, and the d end is the common connection point of the b end and the e end. Therefore, the voltage at the a end is the largest and the current is zero, and the voltage at the e end is zero and the current is the largest. Since the structure of the inverted F antenna includes a grounded metal surface, it can reduce the sensitivity to the grounded metal surface in the RF module, so it is very suitable for on-chip systems. In addition, since the inverted F antenna only needs to use a metal conductor with an appropriate feed line to adjust the position of the short-circuit end of the antenna to the ground plane, the production cost is low and it can be directly welded to the PCB circuit board.

[0028] Figure 2 A PIFA antenna array is provided in the embodiment of the present application, see Figure 2As shown, the PIFA antenna array in this embodiment includes a first antenna 40, a first grounding ring structure 60, a second antenna 50, a second grounding ring structure 70 and an isolation ring structure 120. The first end 130 of the first antenna 40 is connected to the ground plate 10 through the first grounding ring structure 60, and the second end 150 of the first antenna 40 is open. The signal feeding point 20 of the first antenna 40 (see Figure 2 The black triangle on the left in the figure) is arranged between the first end 130 of the first antenna 40 and the second end 150 of the first antenna 40, and the signal feeding point 20 is used to access the feeding signal; the first end 140 of the second antenna 50 is connected to the ground plate 10 through the second grounding ring structure 70, and the second end 160 of the second antenna 50 is open. The signal feeding point 30 of the second antenna 50 (see Figure 2 The black triangle on the right side of the figure) is arranged between the first end 140 of the second antenna 50 and the second end 160 of the second antenna 50; the isolation ring structure 120 is arranged between the first antenna 40 and the second antenna 50, the first side surface of the isolation ring structure 120 is connected to the first grounding ring structure 60, the second side surface of the isolation ring structure 120 is connected to the second grounding ring structure 70, and the third side surface of the isolation ring structure 120 is connected to the grounding plate 10, wherein the first side surface of the isolation ring structure 120 is arranged opposite to the second side surface of the isolation ring structure 120.

[0029] In this embodiment, the first end 130 of the first antenna 40 serves as its matching end and is grounded through the first grounding ring structure 60; the second end 150 of the first antenna 40 is open and serves as the radiation end of the first antenna 40; and the signal feeding point 20 of the first antenna 40 is used to receive a feeding signal. Figure 1 As shown, the first grounding ring structure 60 is connected to the grounding plate 10 and the isolation ring structure 120 respectively, wherein the grounding plate 10 is used as the main ground. The first end 140 of the second antenna 50 is used as its matching end and is grounded through the second grounding ring structure 70, see Figure 1 As shown, the second grounding ring structure 70 is connected to the ground plate 10 and the isolation ring structure 120 respectively.

[0030] In one embodiment, the total length of the first grounding ring structure 60 is 0.43λ, where λ=C / f, C is the speed of light in free space, and f is the antenna operating frequency. The first grounding ring structure 60 can be used as a characteristic impedance length point of the microstrip line, and can effectively eliminate the ground current of the characteristic and the main ground. Further, the other end of the first grounding ring structure 60 is connected to the isolation ring structure 120, and then they are grounded together through the grounding point of the isolation ring structure 120.

[0031] In one embodiment, the first grounding ring structure 60 and the second grounding ring structure 70 are both hollow ring structures.

[0032] In this embodiment, the first antenna 40 is not directly connected to the main ground, and a hollow ring structure (i.e., the first grounding ring structure 60) is used to form a simulated finite ground. The ground current first moves along the ring structure, and the movement length from the main grounding point 100 to the antenna grounding point (i.e., the first end 130 of the first antenna 40) is 0.43λ, which is approximately the length of a half-wave microstrip line. A phase shift of -180 degrees is formed for the ground current, and the first antenna 40 is guided to radiate to the left through the phase shift. In addition, the length of the first grounding ring structure 60 is 0.43λ, and its transmission line characteristic impedance R 环形结构 is about 50Ω, which is similar to the characteristic impedance R of the first antenna 40 天线1 Matching is achieved, so that the residual ground current generated by the mismatch between the radiation impedance of the first antenna 40 and the characteristic impedance of the first grounding ring structure 60 can be prevented from entering the second antenna 50 through the middle isolation ring structure 120, thereby causing interference and reducing isolation.

[0033] In one embodiment, the second antenna 50 is not directly connected to the main ground, and a simulated finite ground is formed by using a second grounding ring structure 70. The ground current first moves along the ring structure, and the moving length from the main grounding point 110 to the antenna grounding point of the second antenna 50 (i.e., the first end 140 of the second antenna 50) is calculated to be 0.43λ (λ=C / f, C is the speed of light in free space, and f is the antenna operating frequency), which is approximately a half-wave length microstrip line. A +180-degree phase shift is formed for the ground current, and the second antenna 50 is guided to radiate to the right through the phase shift. In addition, the length of the second grounding ring structure 70 is 0.43λ (λ=C / f, C is the speed of light in free space, and f is the antenna operating frequency), and its transmission line characteristic impedance R 环形结构 is about 50Ω, and the characteristic impedance R of the second antenna is 50 天线2 Matching is achieved, so that the residual ground current generated by the mismatch between the radiation impedance of the second antenna 50 and the characteristic impedance of the ring structure (ie, the second grounding ring structure 70) can be prevented from entering the second antenna 50 through the middle isolation ring structure 120, thereby causing interference and reducing isolation.

[0034] In one embodiment, the total length of the second grounding ring structure 70 is 0.43λ, which is the characteristic impedance length point of the microstrip line, and can effectively eliminate the ground current between the characteristic and the main ground.

[0035] Furthermore, the other end of the second grounding ring structure 70 is connected to the isolation ring structure 120 , and then they are grounded together through the grounding point of the isolation ring structure 120 .

[0036] In one embodiment, the first grounding ring structure 60 and the isolation ring structure 120 are disposed perpendicularly.

[0037] In this embodiment, the first grounding ring structure 60 and the isolation ring structure 120 are vertically arranged, and the isolation ring structure 120 is arranged between the first grounding ring structure 60 and the second grounding ring structure 70. The two side surfaces of the isolation ring structure 120 (i.e., the first side surface and the second side surface) are respectively connected to the first grounding ring structure 60 and the second grounding ring structure 70, and at the same time, the two ends of the bottom of the isolation ring structure 120 (i.e., the main grounding point 100 and the main grounding point 110) are connected to the main ground (i.e., the grounding plate 10).

[0038] In one embodiment, the total length of the side of the isolation ring structure 120 is 0.5λ, where λ is the wavelength. In this embodiment, the total length of the side of the isolation ring structure 120 is the length from the main grounding point 100 to the main grounding point 110, which is half of the wavelength corresponding to the operating frequency of the PIFA antenna array, that is, 0.5λ, where λ is the wavelength corresponding to the operating frequency of the PIFA antenna array.

[0039] In one embodiment, the isolation ring structure 120 is a hollow structure.

[0040] In this embodiment, the isolation ring structure 120 is "U"-shaped, and the total length of the sides of the isolation ring structure 120 is the length of the U-shaped structure connecting the main grounding point 100 and the main grounding point 110. Specifically, the lengths of the two sides of the U-shaped structure are equal, and the length of each side is 0.25λ, which is at the characteristic impedance matching point of the microstrip line, ensuring that the ground current at the highest point of the isolation ring structure is zero, thereby preventing the residual ground currents of the first antenna 40 and the second antenna 50 from interfering with each other.

[0041] In one embodiment, the first antenna 40 is a single radiating element.

[0042] In one embodiment, the second antenna 50 is a single radiating element.

[0043] In this embodiment, the radiation element of the second antenna 50 is open to radiate to the right, and its grounding end 140 is connected to the second grounding ring structure 70 simulating a finite ground to form an impedance segment to the ground, and is also connected to the spacing segment (90) of the middle isolation ring structure 120 to be connected to the main ground.

[0044] In one embodiment, the length from the signal feeding point of the single radiating element to the second end of the single radiating element is 0.2λ, where λ is the wavelength.

[0045] In one embodiment, the length from the signal feeding point of the single radiating element to the first end of the single radiating element is 0.18λ, where λ is the wavelength.

[0046] In this embodiment, the length of the single radiating element is equivalent to 0.2λ (λ=C / f, C is the speed of light in free space, and f is the antenna operating frequency) from the signal feeding point 30 of the second antenna 50 to the second end 160 of the second antenna 50. The grounding section 140 of the second antenna 50 and the second grounding ring structure 70 simulating a finite ground form an impedance section to the ground, and the length of the impedance section from the signal feeding point 30 of the second antenna 50 to the grounding section 140 of the second antenna 50 is equivalent to 0.18λ (λ=C / f, C is the speed of light in free space, and f is the antenna operating frequency). The common matching of the single radiating element and the grounding section 140 can form a good half-wave resonance.

[0047] In one embodiment, the horizontal first grounded ring structure 60 forms a ground current loop with the first antenna 40, and the horizontal second grounded ring structure 70 forms a ground current loop with the second antenna 50, and the total length of the structure corresponds to 1 / 2 wavelength of the working frequency of the two antennas, thereby forming a complete matching network. The vertical ring structure (i.e., the isolation ring structure 120) is grounded at both ends, and the total length of the side is 1 / 2 wavelength of the antenna working frequency. It is a hollow structure, which can effectively offset the induced current generated by the radiation of the first antenna and the second antenna, and form a reflection wall for the left and right antennas, thereby ensuring sufficient isolation between the two antennas and preventing interference.

[0048] In one embodiment, by providing three ring structures including the first grounding ring structure 60 , the second grounding ring structure 70 and the isolation ring structure 120 , the isolation between the first antenna 40 and the second antenna 50 can be effectively ensured to prevent mutual interference.

[0049] Furthermore, the PIFA antenna array in this embodiment forms a complete electrical signal reflection wall through the arrangement of the middle ring structure, so that both antennas generate clear reverse radiation directions.

[0050] In one embodiment, the radiation ends of the first antenna 40 and the second antenna 50 are in a gradient impedance structure.

[0051] In one embodiment, the first antenna 40 and the second antenna 50 may be printed on a PCB (printed circuit board).

[0052] In one embodiment, the PIFA antenna array in this embodiment is a close-range decoupled PIFA antenna array, which can realize the combination of two antennas in a small space by changing a unique grounding method. The first antenna 40 and the second antenna 50 are divided by a ring-shaped isolation structure 120, and the total side length of the ring-shaped isolation structure 120 is set to 0.5λ, so that the mutual current phases between the two antennas are completely opposite, and the radiation directions of the first antenna and the second antenna are mutually reversed. This can greatly save the space size required to reserve the two antennas for separate use.

[0053] Furthermore, the first antenna 40 and the second antenna 50 are each connected to the main ground through a ring structure. The lengths of the two ring structures are approximately the impedance matching point of the microstrip line, thereby achieving a residual current of the antenna to the ground that is close to zero, thus breaking away from the conventional PIFA method of relying on the main ground to form radiation.

[0054] In one embodiment, the first antenna 40 and the second antenna 50 can be produced using hardware materials and installed by plug-in. They can also be printed on the mainboard PCB. The signal input point is directly connected to the signal line and integrated with the PCB of the entire machine circuit using the antenna, thereby improving the portability and ease of use of the entire terminal device.

[0055] In one embodiment, the first antenna 40 and the second antenna 50 are formed by printing on a PCB and directly integrated with the PCB of a complete circuit using the antenna.

[0056] In one embodiment, the antenna body in the PIFA antenna array in this embodiment is formed by stamping a metal mold, and the antenna is installed in a plug-in manner and is integrated with the PCB of the whole circuit using the antenna.

[0057] In one embodiment, the PIFA antenna array in this embodiment can be used as a high-gain dual-band PIFA planar antenna, and the PIFA antenna array includes a 2.4G main radiation section and a 5G main radiation section. For example, the first antenna 40 includes a 2.4G main radiation section, and the second antenna 50 includes a 5G main radiation section. The length of the main radiation section plus the signal transmission section, the impedance matching section and the signal feeding section is 1 / 4 wavelength of the first specified frequency. At the same time, the length of the signal transmission section, the impedance matching section and the signal feeding section is 1 / 4 wavelength of the second specified frequency, thereby forming a dual frequency. The antenna is installed as a plug-in, and is integrated with the PCB of the whole machine circuit using the antenna. The PCB is a reflector to achieve the goal of high gain.

[0058] In one embodiment, the PIFA antenna array antenna in this embodiment is installed in an assembled manner, and the antenna body is printed on a PCB board. It can be made into a separate PCB antenna and installed on the inner wall of the casing, or it can be printed on the system motherboard to make a board-mounted antenna. Both installation methods can be fed by a 50-ohm coaxial cable and connected to the RF radio frequency system of the Netcom terminal device through a coaxial cable to work.

[0059] In one embodiment, the present application also provides a radio frequency antenna system, which includes the PIFA antenna array as described in any of the above embodiments.

[0060] In the PIFA antenna array and radio frequency antenna system provided by the present application, the PIFA antenna array includes: a first grounding ring structure, a first antenna, a second grounding ring structure, a second antenna and an isolation ring structure, wherein the first end of the first antenna is connected to the ground plate through the first grounding ring structure, the second end of the first antenna is open, and the signal feeding point of the first antenna is arranged between the first end of the first antenna and the second end of the first antenna; the first end of the second antenna is connected to the ground plate through the second grounding ring structure, the second end of the second antenna is open, and the signal feeding point of the second antenna is arranged between the first end of the second antenna and the second end of the second antenna, the isolation ring structure is arranged between the first antenna and the second antenna, the first side surface of the isolation ring structure is connected to the first grounding ring structure, the second side surface of the isolation ring structure is connected to the second grounding ring structure, the third side surface of the isolation ring structure is connected to the ground plate, and the first side surface of the isolation ring structure and the second side surface of the isolation ring structure are arranged opposite to each other, thereby providing a new type of PIFA antenna array, which makes the built-in antenna light, thin and small without reducing the antenna performance.

[0061] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A PIFA antenna array, characterized in that: include: a first grounded ring structure; a first antenna, wherein a first end of the first antenna is connected to a ground plate through the first grounding ring structure, a second end of the first antenna is open, and a signal feeding point of the first antenna is arranged between the first end of the first antenna and the second end of the first antenna; a second grounded ring structure; The first grounding ring structure and the second grounding ring structure are both hollow ring structures; a second antenna, wherein a first end of the second antenna is connected to the ground plate through the second grounding ring structure, a second end of the second antenna is open, and a signal feeding point of the second antenna is arranged between the first end of the second antenna and the second end of the second antenna; an isolation annular structure, disposed between the first antenna and the second antenna, wherein a first side surface of the isolation annular structure is connected to the first grounding annular structure, a second side surface of the isolation annular structure is connected to the second grounding annular structure, and a third side surface of the isolation annular structure is connected to the grounding plate, wherein the first side surface of the isolation annular structure is disposed opposite to the second side surface of the isolation annular structure; The isolation annular structure is in a "U" shape, and the total length of the side length of the isolation annular structure is the length of the U-shaped structure connecting the two ends of the bottom of the isolation annular structure.

2. The PIFA antenna array according to claim 1, characterized in that: The first grounding ring structure is perpendicular to the isolation ring structure.

3. The PIFA antenna array according to claim 1, characterized in that: The total length of the first grounding ring structure is 0.43λ, where λ is a wavelength.

4. The PIFA antenna array according to claim 1, characterized in that: The total length of the side of the isolation ring structure is 0.5λ, where λ is the wavelength.

5. The PIFA antenna array according to claim 1, characterized in that: The isolation annular structure is a hollow structure.

6. The PIFA antenna array according to claim 1, characterized in that: The first antenna is a single radiating element.

7. The PIFA antenna array according to claim 6, characterized in that: The length from the signal feeding point of the single radiating oscillator to the second end of the single radiating oscillator is 0.2λ, where λ is the wavelength.

8. The PIFA antenna array according to claim 6, characterized in that: The length from the signal feeding point of the single radiating oscillator to the first end of the single radiating oscillator is 0.18λ, where λ is the wavelength.

9. A radio frequency antenna system, characterized in that: include: The PIFA antenna array according to any one of claims 1 to 8.

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