CN105896043A - Slot antenna of gate slot ground coplanar waveguide feed capacitance loading stepped-impedance - Google Patents

Abstract

A slot antenna with step impedance fed by a coplanar waveguide fed by grid slots relates to a slot antenna, which includes a dielectric substrate (1), a metal ground (2) on the dielectric substrate (1) and a radiation slot (3 ), a coplanar waveguide feeder (4); there are radiation slots (3) and multiple parallel grid slots (6) on the metal ground (2); the two ends of the radiation slots (3) are short-circuited; the radiation slots ( 3) There are several capacitors (7) connected in parallel across its edge in the middle to form low-resistance slots (8); the rest of the radiation slots (3) are high-resistance slots (9); coplanar waveguide feeders (4) The outer conductor (5) is connected to the metal ground (2), and its terminal inner conductor (12) straddles the high-resistance slot (9) at its edge (11) and is connected to the metal ground (2). The antenna is multi-band operation which reduces antenna size, cross polarization, shadowing and improves isolation.

Description

Slot Antenna with Slot-Ground Coplanar Waveguide Feeding Capacitively Loaded Step Impedance

technical field

The invention relates to a slot antenna, in particular to a slot antenna with step impedance loaded by a coplanar waveguide feeding capacitance of a grid slot.

Background technique

The slot antenna is the dual antenna of the dipole antenna and has a wide range of applications. However, the ordinary slot antenna not only needs half the wavelength of the radiation slot itself, but also needs a large metal ground area around the radiation slot, usually the length of the metal ground is 1/2 larger than the length of the slot One wavelength, the width of the metal ground is one-half wavelength larger than the width of the slot. A larger metal ground will make the slot antenna unsuitable for multiple-input multiple-output (MIMO) applications, resulting in poor cross-polarization of the antenna, which will lead to a decrease in spectral efficiency and channel capacity. At the same time, the impedance of the slot is very large, which also makes it difficult to match the impedance of the slot antenna feeding transmission line. At the same time, the development of modern communication also requires that the antenna can work in multiple frequency bands, and the two frequency bands can be adjusted separately.

Contents of the invention

Technical problem: the purpose of the present invention is to propose a kind of slot antenna of coplanar waveguide feeding capacitance loading step impedance of grid slot, this antenna can not only have a plurality of operating frequency bands, and a plurality of frequency bands can be adjusted separately; This antenna can It reduces the length of the radiation slot and the area of the metal ground, and has the functions of suppressing cross polarization, improving isolation, and reducing shading.

Technical solution: The slot antenna of the present invention with a coplanar waveguide feeding capacitively loaded step impedance includes a dielectric substrate, a metal ground and radiation slot arranged on the dielectric substrate, and a coplanar waveguide feeder line; one side of the dielectric substrate is The metal ground and the coplanar waveguide feeder, the ground plane of the coplanar waveguide feeder is the metal ground; there are radiation slots on the metal ground, the shape of the radiation slot is rectangular, and the radiation slot is located in the center of the metal ground; there are multiple parallel grid slots on the metal ground The grid slot array is formed, the shape of the grid slot is rectangular, the grid slot is located around the radiation slot, and the grid slot and the radiation slot are perpendicular to each other; one end of the grid slot is short-circuited; the other end of the grid slot is open and located at the edge of the dielectric substrate; The two ends of the radiation slot are short-circuited; in the middle part of the radiation slot, several capacitors are connected in parallel across the two edges of the radiation slot, so that the characteristic impedance of the middle part of the radiation slot becomes lower, forming a low-resistance slot; the radiation slot The rest of the slot is a high-resistance slot, and the high-resistance slot and the low-resistance slot together form a step impedance radiation slot, producing a low-frequency operating band with a lower frequency and a high-frequency operating band with a higher frequency; coplanar One end of the waveguide feeder is the port of the antenna, and the conductor at the other end of the coplanar waveguide feeder crosses the high-resistance slot, and is connected to the metal ground at the edge of the high-resistance slot.

Changing the thickness, permeability and permittivity of the dielectric substrate can change the characteristic impedance of the high-resistance slot and the low-resistance slot, change the high-to-low impedance ratio of the step impedance radiation slot, and then change the antenna's low-frequency working frequency band. frequency and the operating frequency of the high-frequency operating band.

By changing the length of the low-resistance slot and the position of the low-resistance slot in the radiation slot, the electrical length of the radiation slot can be adjusted to achieve different degrees of miniaturization of the antenna, and the working frequency and The operating frequency of the high-frequency operating frequency band.

Changing the spacing between adjacent grid slots in the grid slot array, the width of the grid slots, and the distance between the short-circuit end of the grid slots and the radiation slot can change the working frequency of the antenna, the width of the working frequency band and the electrical length of the radiation slot.

Changing the number, capacitance and spacing of the loading capacitors can adjust the characteristic impedance of the low-resistance slot, change the high-to-low impedance ratio of the step impedance radiation slot, and then change the working frequency of the antenna's low-frequency working frequency band and high-frequency working frequency band. frequency.

Changing the width of the radiation slot can adjust the characteristic impedance of the low-resistance slot and the high-resistance slot, change the high-to-low impedance ratio of the step impedance radiation slot, and then change the working frequency of the low-frequency working frequency band and the high-frequency working frequency band of the antenna. working frequency.

The electrical length of the grid slot should not be taken as a quarter, so as to avoid causing resonant radiation and causing cross-polarization rise.

Capacitors are loaded in parallel to the two edges of the radiation slot, which not only reduces the characteristic impedance of the slot transmission line to easily match the feed transmission line, but also reduces the phase velocity of the slot transmission line, reducing the length of the half-wavelength radiation slot. Small, realize the miniaturization of the radiation slot and the antenna. The working frequency of the low-frequency operating frequency band and the operating frequency of the high-frequency operating frequency band of the slot antenna with coplanar waveguide feeding capacitance loaded with step impedance on the grid slot ground are mainly determined by the resonant frequency of the radiation slot, but the size of the metal ground, coplanarity The position where the waveguide feeder conductor is connected to the radiation slot can also adjust the working frequency and matching degree of the antenna. Since the radiation slots have both low-resistance slots and high-resistance slots, the radiation slots with step impedance are formed, which not only makes the antenna miniaturized, reduces the cross polarization, but also reduces the size of the metal ground, and It is also possible to make the antenna have multiple working frequency bands, and by changing the relative length and impedance of the low-resistance slot and the high-resistance slot, the positions of the two working frequency bands can be adjusted respectively. The grating on the metal ground forms a periodic load on the radiation slot, which makes the radiation slot a periodic slow-wave structure, further reducing the electrical size of the antenna; Vertically, the current along the direction of the radiation slot on the metal ground is suppressed, and the remaining current distribution along the direction of the radiation slot is more concentrated, thereby reducing the cross-polarized radiation and reducing the size of the metal ground.

Beneficial effect: the beneficial effect of the slot antenna of the present invention is that the grid slot ground coplanar waveguide feeding capacitor loads step impedance, the antenna can reduce the electrical size of the whole antenna, realize miniaturization, and at the same time, the antenna can not only have multiple A frequency band, and multiple frequency bands can be adjusted separately, and also has the function of suppressing the cross-polarization of the antenna.

Description of drawings

Fig. 1 is a schematic diagram of the overall structure of a slot antenna with a coplanar waveguide feeding capacitor loaded with a step impedance.

In the figure there are: dielectric substrate 1, metal ground 2, radiation slot 3, coplanar waveguide feeder 4, ground plane 5, grid slot 6, capacitor 7, low resistance slot 8, high resistance slot 9, port 10, edge 11 and conductor 12.

detailed description

The present invention will be further described below in conjunction with drawings and embodiments.

The embodiment adopted by the present invention is: the slot antenna of the coplanar waveguide fed by the grating ground coplanar waveguide and the step impedance is loaded with a step impedance, including a dielectric substrate 1, a metal ground 2 and a radiation slot 3 arranged on the dielectric substrate 1, and a coplanar waveguide The feeder 4; one side of the dielectric substrate 1 is the metal ground 2 and the coplanar waveguide feeder 4, and the ground plane 5 of the coplanar waveguide feeder 4 is the metal ground 2; there is a radiation slot 3 on the metal ground 2, and the shape of the radiation slot 3 is Rectangular, the radiation slot 3 is located in the center of the metal ground 2; the grid slit 6 array formed by a plurality of parallel grid slits 6 on the metal ground 2, the shape of the grid slit 6 is rectangular, the grid slit is located around the radiation slot 3, the grid slit 6 and the radiation slot 3 are perpendicular to each other; one end of the grid slot 6 is short-circuited; the other end of the grid slot 6 is open and located at the edge of the dielectric substrate 1; both ends of the radiation slot 3 are short-circuited; in the middle part of the radiation slot 3, there are several The capacitor 7 is connected in parallel across the two edges of the radiation slot 3, so that the characteristic impedance of the middle part of the radiation slot 3 becomes lower, forming a low-resistance slot 8; the rest of the radiation slot 7 is a high-resistance slot 9. The resistance slot 9 and the low-resistance slot 8 together form the step impedance radiation slot 3, which produces a lower frequency low-frequency operating frequency band and a higher frequency high-frequency operating frequency band; one end of the coplanar waveguide feeder 4 is the antenna The port 10 , the conductor 12 at the other end of the coplanar waveguide feeder 4 crosses the high-resistance slot 9 and is connected to the metal ground 2 at the edge 11 of the high-resistance slot 9 .

Changing the thickness, magnetic permeability and dielectric constant of the dielectric substrate 1 can change the characteristic impedance of the high-resistance slot 9 and the low-resistance slot 8, change the high-to-low impedance ratio of the step impedance radiation slot 3, and then change the low frequency of the antenna The working frequency of the working frequency band and the working frequency of the high frequency working frequency band.

By changing the length of the low-resistance slot 8 and the position of the low-resistance slot 8 in the radiation slot 3, the electrical length of the radiation slot 3 can be adjusted to achieve different degrees of antenna miniaturization, and the low-frequency working frequency band of the antenna can also be changed The operating frequency and the operating frequency of the high-frequency operating frequency band.

Changing the distance between adjacent grid slots 6 in the array of grid slots 6, the width of grid slots 6, and the distance between the short-circuit end of grid slots 6 and the radiation slot 3 can change the operating frequency of the antenna, the width of the working frequency band, and the width of the radiation slot 3. electrical length.

By changing the quantity, capacitance and spacing of the loading capacitors (7), the characteristic impedance of the low-resistance slot 8 can be adjusted, the high-to-low impedance ratio of the step impedance radiation slot 3 can be changed, and the working frequency and high The working frequency of the frequency working frequency band.

Changing the width of the radiation slot 3 can adjust the characteristic impedance of the low-resistance slot 8 and the high-resistance slot 9, change the high-to-low impedance ratio of the step impedance radiation slot 3, and then change the working frequency and high frequency of the low-frequency working frequency band of the antenna. The working frequency of the frequency working frequency band.

The electrical length of the grid slot 6 should not be set at a quarter, so as to avoid causing resonant radiation and causing an increase in cross polarization.

The working frequency of the low-frequency operating frequency band and the operating frequency of the high-frequency operating frequency band of the slot antenna of the coplanar waveguide feeding capacitor loaded with step impedance by the grid slot are mainly determined by the resonant frequency of the radiation slot 3, but the size of the metal ground 2, The position where the conductor 12 of the coplanar waveguide feeder 4 is connected to the radiation slot 3 can also adjust the working frequency and matching degree of the antenna. Since the radiation slot 3 has both a low-resistance slot 8 and a high-resistance slot 9, a radiation slot 3 with a step impedance is formed, which not only makes the antenna miniaturized, reduces cross-polarization, but also reduces the metal ground 2, but also can make the antenna have multiple working frequency bands, and change the relative length, position and impedance of the low-resistance slot 8 and the high-resistance slot 9, and the positions of the two working frequency bands can be adjusted respectively. The grid slot 6 on the metal ground 2 forms a periodic load on the radiation slot 3, and makes the radiation slot 3 become a periodic slow wave structure, which further reduces the electrical size of the antenna; at the same time, due to the direction of the grid slot 6 It is perpendicular to the direction of the radiation slot 3, suppressing the current on the metal ground 2 along the direction of the radiation slot 3, and making the remaining current distribution along the direction of the radiation slot 3 more concentrated, thereby reducing the cross-polarized radiation , also reduces the size of the metal ground 2.

In terms of technology, the slot antenna with the coplanar waveguide feeding capacitor loaded with step impedance can adopt either the ordinary printed circuit board (PCB) process, or the low temperature co-fired ceramic (LTCC) process or CMOS, Si-based chip and other integrated circuit technology. Capacitor 7 can select the chip capacitor 7 of the corresponding package according to the working frequency, and select the width of the low-resistance slot 8 according to the distance between the electrodes of the two pins of the capacitor 7 .

According to the above, the present invention can be realized.

Claims (6)

1. the slot antenna of a grid seam ground coplanar wave guide feedback capacitive load Stepped Impedance, it is characterised in that this antenna bag Metal ground (2) include medium substrate (1), being arranged on medium substrate (1) and the radiation line of rabbet joint (3), co-planar waveguide feedback Line (4)；The one side of medium substrate (1) is metal ground (2) and coplanar waveguide feeder line (4), coplanar waveguide feeder line (4) Ground plane (5) be exactly metal ground (2)；The radiation line of rabbet joint (3), the shape of the radiation line of rabbet joint (3) is had on metal ground (2) Shape is rectangle, the center of the radiation line of rabbet joint (3) with being positioned at metal (2)；Upper a plurality of parallel gate seam (6) of metal ground (2) Grid seam (6) array constituted, the shape of grid seam (6) is rectangle, and grid seam is positioned at the surrounding of the radiation line of rabbet joint (3), grid Seam (6) is mutually perpendicular to the radiation line of rabbet joint (3)；The short at one end of grid seam (6)；The other end open circuit of grid seam (6), It is positioned at the edge of medium substrate (1)；Two terminal shortcircuits of the radiation line of rabbet joint (3)；At the radiation line of rabbet joint (3) mid portion, Several electric capacity (7) is had to be connected in parallel across radiating two edges of the line of rabbet joint (3) so that the radiation line of rabbet joint (3) mid portion Characteristic impedance step-down, formed the low-resistance line of rabbet joint (8)；The remainder of the radiation line of rabbet joint (3) is the high resistant line of rabbet joint (9), high The resistance line of rabbet joint (9) constitutes Stepped Impedance with the low-resistance line of rabbet joint (8) together with and radiates the line of rabbet joint (3), produces relatively low low of frequency Frequently working band and the higher high-frequency work frequency band of a frequency；One end of coplanar waveguide feeder line (4) is the port of antenna (10), the conductor (12) of coplanar waveguide feeder line (4) other end strides across the high resistant line of rabbet joint (9), in the high resistant line of rabbet joint (9) Edge (11), with metal (2) be connected.

The slot antenna of a kind of grid the most according to claim 1 seam ground coplanar wave guide feedback capacitive load Stepped Impedance, It is characterized in that change medium substrate (1) thickness, pcrmeability and dielectric constant, thus it is possible to vary the high resistant line of rabbet joint (9) and The characteristic impedance of the low-resistance line of rabbet joint (8), changes the height impedance ratio of the Stepped Impedance radiation line of rabbet joint (3), and then changes antenna The operating frequency of low frequency operation frequency band and the operating frequency of high-frequency work frequency band.

The slot antenna of a kind of grid the most according to claim 1 seam ground coplanar wave guide feedback capacitive load Stepped Impedance, It is characterized in that changing the length of the low-resistance line of rabbet joint (8), the low-resistance line of rabbet joint (8) position in the radiation line of rabbet joint (3), can With the electrical length of the regulation radiation line of rabbet joint (3), to realize antenna miniaturization in various degree, it is also possible to change the low of antenna Frequently the operating frequency of working band and the operating frequency of high-frequency work frequency band.

The slot antenna of a kind of grid the most according to claim 1 seam ground coplanar wave guide feedback capacitive load Stepped Impedance, It is characterized in that changing the adjacent gate seam spacing of (6) in grid seam (6) array, the grid seam width of (6), grid seam (6) Short-circuit end is from the distance of the radiation line of rabbet joint (3), thus it is possible to vary the operating frequency of antenna, the width of working band and radius The electrical length of seam (3).

The slot antenna of a kind of grid the most according to claim 1 seam ground coplanar wave guide feedback capacitive load Stepped Impedance, It is characterized in that changing quantity, capacitance and the spacing of loading capacitance (7), the characteristic resistance of the low-resistance line of rabbet joint (8) can be regulated Anti-, change the height impedance ratio of the Stepped Impedance radiation line of rabbet joint (3), and then change the work of the low frequency operation frequency band of antenna Frequency and the operating frequency of high-frequency work frequency band.

The slot antenna of a kind of grid the most according to claim 1 seam ground coplanar wave guide feedback capacitive load Stepped Impedance, It is characterized in that changing the width of the radiation line of rabbet joint (3), the low-resistance line of rabbet joint (8) and the spy of the high resistant line of rabbet joint (9) can be regulated Property impedance, change the height impedance ratio of the Stepped Impedance radiation line of rabbet joint (3), and then change the low frequency operation frequency band of antenna Operating frequency and the operating frequency of high-frequency work frequency band.