Adjustable electric small pcb antenna

Abstract

The application provides a tunable electric small PCB antenna, which comprises a double-sided copper-clad PCB circuit board and a voltage control matching circuit; a circle of metal vias is distributed on the edge of the double-sided copper-clad PCB circuit board, the metal vias connect the upper and lower two layers of surface copper-clad plates of the double-sided copper-clad PCB circuit board, and the copper-clad plates are grounded; a notch slot is formed on one side of the PCB circuit board, the notch slot comprises a notch located in the middle of the PCB circuit board and a slit connecting the notch and the edge of the PCB circuit board; a group of pads are arranged on the two sides of the notch slot; and the voltage control matching circuit is electrically connected with the pads. In the application, the PCB antenna does not need a separate radiator, and the space occupied by the antenna can be effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of antenna, in particular, to an adjustable electrically small PCB antenna. BACKGROUND

[0002] With the development of wireless communication technology, mobile terminals gradually develop towards multi-function, miniaturization and high performance in practical research and application. As a component used for receiving and transmitting signals in wireless communication equipment, the antenna is widely used in various fields. At present, the requirement of more functions of mobile terminals while reducing the volume leads to smaller and smaller available space for the antenna. Moreover, with more functions, more frequency bands will be integrated on the antenna at the same time, and the antenna needs to be flush or conformal with the surface of the carrier, which promotes the research of small-sized antenna and low-profile antenna.

[0003] PCB antenna is widely used in modern microwave transceiver system and is an important part of microwave devices. However, there are some problems in actual production and application. The main problem is that there is a deviation between the test results after physical processing and the theoretical results of software simulation. Different batches of the same type of PCB board produced in actual processing will have different parameters such as loss tangent, dielectric constant and thickness, but the PCB antenna parameters simulated by software are set according to the theoretical values. This leads to a certain error between the theoretical results of software simulation and the test results of the actual antenna processed. Moreover, when the temperature and pressure of the environment change greatly, the frequency of the PCB antenna will also shift. SUMMARY

[0004] In view of the defects in the prior art, the purpose of the present application is to provide an adjustable electrically small PCB antenna, which can effectively reduce the occupied space of the antenna without a separate radiator and belongs to an electrically small PCB antenna. The PCB antenna can be better integrated with the system and the antenna radiation frequency can be changed through digital coding.

[0005] The adjustable electrically small PCB antenna provided by the present application comprises a double-sided copper-clad PCB circuit board and a voltage control matching circuit.

[0006] The double-sided copper-clad PCB circuit board is provided with a circle of metal vias at the edge, the metal vias connect the upper and lower surfaces of the double-sided copper-clad PCB circuit board, and the copper-clad board is grounded.

[0007] A notch slot is formed on one side of the PCB circuit board, the notch slot comprises a notch in the middle of the PCB circuit board and a gap connecting the notch and the edge of the PCB circuit board, and a group of pads are arranged on both sides of the notch slot.

[0008] The voltage control matching circuit is electrically connected to the pads.

[0009] Preferably, the voltage control matching circuit comprises a feed port, a first capacitor, a second capacitor, a varactor diode, an inductor and a voltage controller.

[0010] The feed port is connected to one end of the first capacitor, the other end of the first capacitor is connected to the negative electrode of the varactor diode and one end of the second capacitor, and the other end of the second capacitor is connected to the pad.

[0011] The positive electrode of the voltage controller is connected to the negative electrode of the varactor diode through the inductor, the positive electrode of the varactor diode is connected to the ground copper-clad plate, and the negative electrode of the voltage controller is connected to the copper-clad plate.

[0012] Preferably, the feed port is used for inputting signals into the voltage control matching circuit to generate resonance, so that the resonant current flowing along the edge of the PCB circuit board generates effective radiation.

[0013] Preferably, the voltage controller changes the output voltage size through digital coding.

[0014] Preferably, the capacitance value of the varactor diode is changed by controlling the voltage controller to output different voltage values to change the antenna radiation frequency.

[0015] Preferably, the relationship between the antenna radiation frequency f (GHz) and the voltage controller voltage v (V) is:

[0016] f = -0.005 * v 2 + 0.135 * v + 1.604.

[0017] Preferably, the varactor diode is used to eliminate the influence of production errors of the PCB circuit board on the antenna radiation frequency through voltage adjustment.

[0018] Preferably, the PCB circuit board adopts an FR-4 double-sided PCB circuit board.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] The present application does not need a separate radiator and belongs to an electrically small antenna, which can effectively reduce the occupied space of the antenna and better integrate with active devices and microwave circuits;

[0021] The present application can adjust the shift of the antenna resonance frequency caused by the deviation between the actual production of the PCB board and the theoretical parameter setting, or the shift of the PCB antenna frequency caused by the dramatic changes in environmental temperature, pressure, etc., and adjust the antenna radiation frequency through the voltage controller in the case where the conditions do not allow the replacement of components.

[0022] The application has the advantages of miniaturization, low profile, easy integration, low cost, simple structure, easy processing and the like. BRIEF DESCRIPTION OF DRAWINGS

[0023] Other features, objects, and advantages of the application will become more apparent from the following detailed description of non-limiting embodiments, when read in conjunction with the accompanying drawings:

[0024] Figure 1 is a specific structure diagram of the adjustable electric small PCB antenna in the embodiment of the application.

[0025] Figure 2 is a structure distribution diagram of the transceiving signal system of the adjustable electric small PCB antenna in the embodiment of the application.

[0026] Figure 3 is a measured S 11 parameter variation diagram of the novel adjustable electric small PCB antenna under different voltages in the embodiment of the application.

[0027] In the drawings:

[0028] 1 - double-sided copper-clad PCB circuit board, 2 - notch slot, 3 - metal via, 4 - pad, 5 - feed port, 6 - first capacitor, 7 - second capacitor, 8 - varactor diode, 9 - inductor, 10 - voltage controller. DETAILED DESCRIPTION

[0029] The application will be described in detail below with specific embodiments. The following embodiments will help those skilled in the art to further understand the application, but do not limit the application in any form. It should be pointed out that, for those skilled in the art, without departing from the concept of the application, a number of modifications and improvements can be made. These all belong to the protection scope of the application.

[0030] Figure 1 is a specific structure diagram of the novel adjustable electric small PCB antenna in the embodiment of the application, as shown in the figure, the adjustable electric small PCB antenna provided by the application includes a double-sided copper-clad PCB circuit board 1 and a voltage control matching circuit. Figure 1

[0031] The double-sided copper-clad PCB circuit board 1 has a circle of metal vias 3 distributed on the edge, the metal vias 3 connect the upper and lower two layers of surface copper-clad plates, and the copper-clad plates are grounded.

[0032] The PCB circuit board has a notch slot 2 on one side, the notch slot is composed of a circular notch in the middle of the PCB circuit board and a rectangular gap connecting the circular notch and the edge of the PCB circuit board.

[0033] A group of pads 4 are placed on both sides of the notch slot 2.

[0034] ​The voltage control matching circuit comprises a first capacitor 6, a second capacitor 7, an inductor 9 and a varactor 8 connected by microstrip lines;

[0035] The feed port 5 is connected to the first capacitor 6 and the second capacitor 7 and is connected to the PCB circuit board 1 through the solder pad 4.

[0036] The positive electrode of the voltage controller 10 changes the voltage of the varactor 8 through the inductor 9 to change the capacitance value, and the negative electrode of the voltage controller 10 and the positive electrode of the varactor 8 are connected to the ground copper-clad plate. The signal enters the voltage control matching circuit through the feed port 5 to generate resonance, and the effective radiation is generated by the resonant current flowing along the edge of the PCB board.

[0037] An electrically small antenna refers to an antenna whose maximum geometric size is much smaller than the working wavelength. The conclusion obtained by analyzing the electrically small antenna using the lumped parameter theory or the spherical wave model theory is that:

[0038] The quality factor Q of the antenna and the cube of the radius of the antenna volume sphere measured by the wavelength are inversely proportional. The smaller the electric size of the antenna, the higher the Q value, and the narrower the working frequency band.

[0039] Therefore, the basic limit of the electrically small antenna is determined by the minimum working frequency band allowed by the electrically small antenna. If the size of the electric size is used as the standard for judging the electrically small antenna, Wheeler H.A.Wheeler defines that:

[0040]

[0041] In the formula, l is the maximum size of the antenna, and lambda is the working wavelength.

[0042] The adjustable PCB antenna in the embodiment of the application does not need a separate radiator, and the structural size of the notch groove and the voltage control matching circuit is 10.3mm*8.3mm. Since the antenna radiation frequency is adjustable, the wavelength is 150mm when 2GHz is taken as an example. According to the electric size, it is determined that the antenna belongs to an electrically small antenna.

[0043] Figure 2 The structure distribution diagram of the adjustable electrically small PCB antenna transceiver signal system in the embodiment of the application is shown in FIG. 1. Figure 2 As shown in FIG. 1, the signal generated by the wireless transceiver is amplified by the power amplifier, reaches the adjustable electrically small PCB antenna provided by the application through the transceiver converter, the voltage controller adjusts the antenna frequency to generate effective radiation. The signal in space is received by the new adjustable electrically small PCB antenna, reaches the low-noise amplifier after the transceiver converter, and then enters the wireless transceiver.

[0044] The embodiment of the application and the implementation process thereof are as follows:

[0045] The antenna is made by cutting a circular notch with a radius of 2mm on one side of the long side of a PCB board 1 with a length of 42mm, a width of 21mm, and a height of 0.6mm. The circular notch is connected to the edge of the board by a rectangular gap with a length of 2mm and a width of 1mm. The circular notch and the rectangular gap together form the notch slot 2.

[0046] PCB 1 uses FR4 dielectric with a dielectric constant of 4.3 and a copper thickness of 0.035mm. A series of metal vias 3 with a radius of 0.15mm are distributed on the notch 2 and the edge of PCB 1. The metal vias 3 are spaced 2mm apart and connect the upper and lower copper clad boards.

[0047] The voltage control matching circuit includes a 0.6mm wide microstrip line connecting a first capacitor 6, a second capacitor 7, a varactor diode 8, and an inductor 9. The signal enters the voltage control matching circuit through the feed port 5, generating a resonant current that then effectively radiates from the edge of the PCB board. The output voltage of the voltage controller 10 is changed via digital encoding. The positive terminal of the voltage controller 10 changes the voltage of the varactor diode 8 through the inductor 9, thereby changing the capacitance value and altering the antenna's radiation frequency.

[0048] Figure 3 The measured voltage S values ​​of the novel adjustable small PCB antenna under different voltages in this embodiment of the invention are shown below. 11 Parameter variation graph, such as Figure 3 As shown, the measured S of the adjustable small PCB antenna in this invention 11 The parameter variation graph shows that by changing the output voltage of the voltage controller through digital encoding, different voltages are applied across the varactor diode to adjust the resonant frequency of the PCB antenna. The voltage controller 10 outputs different voltage values ​​to change the capacitance of the varactor diode, thereby altering the antenna radiation frequency. The relationship between the antenna radiation frequency f (GHz) and the voltage controller voltage v (V) is f = -0.005 * v. 2 +0.135*v+1.604.

[0049] from Figure 3 S 11 The graph shows that the antenna has filtering characteristics.

[0050] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. An adjustable electrically small PCB antenna, characterized by, The utility model relates to a kind of antenna and voltage control matching circuit, including: Double-sided copper-clad PCB circuit board (1) and voltage control matching circuit; The double-sided copper-clad PCB circuit board (1) edge distributes a circle of metal via (3), the metal via (3) is connected with the upper and lower two layers surface copper-clad plate of double-sided copper-clad PCB circuit board (1), and the copper-clad plate is grounded; The PCB circuit board (1) has a notch slot (2) on one side, the notch slot (2) includes a notch in the PCB circuit board and a slit connecting the notch and the edge of the PCB circuit board;A group of pads (4) are placed on both sides of the notch slot (2); The voltage control matching circuit is electrically connected to the pads (4);The voltage control matching circuit includes a feed port (5), a first capacitor (6), a second capacitor (7), a varactor diode (8), an inductor (9) and a voltage controller (10); The feed port (5) is connected to one end of the first capacitor (6), and the other end of the first capacitor (6) is connected to the negative electrode of the varactor diode (8) and one end of the second capacitor (7), and the other end of the second capacitor (7) is connected to the pads (4); The positive electrode of the voltage controller (10) is connected to the negative electrode of the varactor diode (8) through the inductor (9), the positive electrode of the varactor diode (8) is connected to the ground copper-clad plate, the negative electrode of the voltage controller (10) is connected to the copper-clad plate, and the capacitance value of the varactor diode is changed by controlling the output voltage value of the voltage controller (10) to change the antenna radiation frequency.

2. The tunable electrically small PCB antenna of claim 1, wherein, The feed port (5) is used to input signals into the voltage control matching circuit to generate resonance, so that the resonant current flowing along the edge of the PCB circuit board produces effective radiation.

3. The tunable electrically small PCB antenna of claim 1, wherein, The voltage controller (10) changes the output voltage size by digital coding.

4. The tunable electrically small PCB antenna of claim 1, wherein, The relationship between the antenna radiation frequency f (GHz) and the voltage controller voltage v (V) is as follows: f = -0.005 * v 2 + 0.135 * v + 1.

604.

5. The tunable electrically small PCB antenna of claim 1, wherein, The varactor diode is used to eliminate the influence of production errors on the antenna radiation frequency by voltage adjustment.

6. The tunable electrically small PCB antenna of claim 1, wherein, The PCB circuit board (1) uses FR-4 double-sided PCB circuit board.

Images