CN105703070A - Tri-polarized slot antenna of grid slit ground coplanar waveguide feed capacitor loaded step impedance - Google Patents

Abstract

The three-polarization slot antenna of grid slot coplanar waveguide feeding capacitance loading step impedance relates to a slot antenna, and the antenna is composed of three mutually perpendicularly placed single-polarization antennas (13); each antenna (13) includes Dielectric substrate (1), metal ground (2) and radiation slots (3) on the dielectric substrate (1), coplanar waveguide feeder (4); metal ground (2) has radiation slots (3) and multiple parallel Grid slot (6); both ends of the radiation slot (3) are short-circuited; there are several capacitors (7) connected in parallel across the edge of the radiation slot (3) to form a low-resistance slot (8); the radiation slot ( 3) The remaining part is a high-resistance slot (9); the outer conductor (5) of the coplanar waveguide feeder (4) is connected to the metal ground (2), and the inner conductor (12) at its end crosses the high-resistance slot (9) in the Its edge (11) is connected with metal ground (2). The antenna operates in multiple bands, allowing for reduced antenna size, cross-polarization, shadowing, and improved isolation.

Description

Triple-polarization slot antenna with step impedance loaded by capacitively fed coplanar waveguide

technical field

The invention relates to a slot antenna, in particular to a three-polarization slot antenna in which the coplanar waveguide feeding capacitance of the grid slot loads a step impedance.

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. Multi-polarization MIMO can effectively improve spectrum efficiency and channel capacity. In order to apply MIMO technology to small terminals, antennas with different polarizations need to be co-located. A large metal ground will have a shielding effect on the radiation of the antenna, making the slot antenna unsuitable for co-located multiple-input multiple-output (MIMO) applications, especially when used as a multi-polarized antenna, a large metal ground will cause the antenna to Poor cross-polarization and poor isolation between antenna ports lead to a reduction 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 three-polarized slot antenna with coplanar waveguide feeding capacitance loading step impedance of grid slot, this antenna can not only have a plurality of operating frequency bands, but also a plurality of frequency bands can be adjusted separately; The antenna can reduce 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 triple-polarized slot antenna of the present invention, which is fed by a coplanar waveguide with a grid slot, includes three vertically placed single-polarized slot antennas with a capacitance-loaded step impedance; each single The polarized grid slot capacitively loaded step impedance antenna includes a dielectric substrate, a metal ground and a radiation slot arranged on the dielectric substrate, and a coplanar waveguide feeder; one side of the dielectric substrate is a metal ground and a coplanar waveguide feeder, and the coplanar waveguide The ground plane of the feeder is the metal ground; there are radiation slots on the metal ground, the shape of the radiation slots is rectangular, and the radiation slots are located in the center of the metal ground; the grid slot array is composed of multiple parallel grid slots on the metal ground, and the shape of the grid slots 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, located on the edge of the dielectric substrate; both ends of the radiation slot are short-circuited; in the radiation slot 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 rest of the radiation slot is a high-resistance slot, high The resistance slot and the low-resistance slot together form a step impedance radiation slot, 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 is the port of the antenna, coplanar The conductor at the other end of the 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 working frequency band and the high-frequency working frequency band of the three-polarized slot antenna with coplanar waveguide feeding capacitor 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 , The position where the coplanar waveguide feeder conductor is connected to the radiation slot can also adjust the operating frequency and matching degree of the antenna. Since the radiation slots have both low-resistance slots and high-resistance slots, radiation slots with step impedance are formed, which not only makes the antenna miniaturized, reduces cross-polarization, but also reduces the size of the metal ground, The isolation is improved and the shielding effect of the metal ground is reduced, and the antenna can have multiple operating frequency bands, and the positions of the two operating frequency bands can be adjusted by changing the relative length and impedance of the low-resistance slot and the high-resistance slot. 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; Vertical, which suppresses the current along the direction of the radiation slot on the metal ground, and makes the remaining current distribution along the direction of the radiation slot more concentrated, thereby reducing cross-polarized radiation and improving the isolation between antenna ports. The size of the metal ground is reduced, and the shielding effect of the metal ground is reduced.

Beneficial effect: the beneficial effect of the three-polarization slot antenna with grid slot ground coplanar waveguide feeding capacitor loading step impedance of the present invention is that the antenna can reduce the electrical size of the entire antenna and realize miniaturization, and the antenna not only There can be multiple frequency bands, and the multiple frequency bands can be adjusted separately. It also has the functions of suppressing the cross-polarization of the antenna, improving the isolation between ports, and reducing the shielding of the metal ground.

Description of drawings

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

Fig. 2 is a schematic structural diagram of a single-polarized slotted coplanar waveguide feeding capacitively loaded step impedance triple-polarized slot antenna.

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. The conductor 12 and the capacitively loaded step-impedance antenna 13 of the single-polarized grid slot.

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 three-polarization slot antenna of the coplanar waveguide feeding capacitively loaded step impedance of the grid slot includes three vertically placed single-polarized grid slot ground capacitance loaded step impedance antennas 13 ; The capacitively loaded step impedance antenna 13 of each single-polarized grid slot includes a dielectric substrate 1, a metal ground 2 disposed on the dielectric substrate 1, a radiation slot 3, and a coplanar waveguide feeder 4; one side of the dielectric substrate 1 is The metal ground 2 and the coplanar waveguide feeder 4, 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, the shape of the radiation slot 3 is rectangular, and the radiation slot 3 is located on the metal ground The center of 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, and 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, several capacitors 7 are connected in parallel across the radiation slot The two edges of 3 make the characteristic impedance of the middle part of the radiation slot 3 become lower, forming a low-resistance slot 8; the rest of the radiation slot 7 is a high-resistance slot 9, a high-resistance slot 9 and a low-resistance slot 8 together constitute the step impedance radiation slot 3, producing a low-frequency operating band with a lower frequency and a high-frequency operating band with a higher frequency; one end of the coplanar waveguide feeder 4 is the port 10 of the antenna, and the other end of the coplanar waveguide feeder 4 is The conductor 12 at one end 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 operating frequency of the low-frequency operating frequency band and the operating frequency of the high-frequency operating frequency band of the three-polarized slot antenna of the coplanar waveguide feeding capacitor loaded with step impedance by the grid slot ground are mainly determined by the resonant frequency of the radiation slot 3, but the metal ground 2 The size of the coplanar waveguide feeder 4 and the position where the conductor 12 of the coplanar waveguide feeder 4 is connected to the radiation slot 3 can also adjust the operating 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 The size of 2 improves the isolation and reduces the shielding effect of the metal ground 2, and can also make the antenna have multiple operating frequency bands, and change the relative length, position and impedance of the low-resistance slot 8 and the high-resistance slot 9, respectively. Adjust the position of the two working frequency bands. 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 , which improves the isolation between antenna ports, reduces the size of the metal ground 2, and reduces the shielding effect of the metal ground 2.

In terms of technology, the three-polarized slot antenna with coplanar waveguide feeding capacitance loaded with step impedance can adopt either ordinary printed circuit board (PCB) technology, low temperature co-fired ceramic (LTCC) technology or CMOS , Si substrate 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 . In terms of manufacture, the three single-polarized slotted capacitance-loaded step impedance antennas 13 can be vertically installed together through slots, or vertically bonded together by adhesive, or both methods can be used together.

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

Claims (6)

1. A three-polarized slot antenna with coplanar waveguide feeding capacitance loading step impedance of grid slot, characterized in that the antenna includes three vertically placed single-polarized grid slot capacitance loading step impedance antennas (13); the capacitance-loaded step impedance antenna (13) of each single-polarized grid slot includes a dielectric substrate (1), a metal ground (2) and a radiation slot (3) arranged on the dielectric substrate (1) 1. Coplanar waveguide 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) Radiation slot (3) is arranged on metal ground (2), and the shape of radiation slot (3) is rectangle, and radiation slot (3) is positioned at the center of metal ground (2); On metal ground (2), a plurality of parallel The grid slit (6) array formed by the grid slit (6), the shape of the grid slit (6) is rectangular, the grid slit is located around the radiation slot (3), and the grid slit (6) and the radiation slot (3) are perpendicular to each other One end of the grid slit (6) is short-circuited; the other end of the grid slit (6) is open and located at the edge of the dielectric substrate (1); the two ends of the radiation slot (3) are short-circuited; in the middle part of the radiation slot (3), Several capacitors (7) are 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 radiation slot (3) ) is the high-resistance slot (9), and the high-resistance slot (9) and the low-resistance slot (8) together form a step impedance radiation slot (3), producing a low-frequency operating frequency band with a lower frequency and A high-frequency operating frequency band with a higher frequency; one end of the coplanar waveguide feeder (4) is the port (10) of the antenna, and the conductor (12) at the other end of the coplanar waveguide feeder (4) crosses the high-resistance slot (9) , at the edge (11) of the high-resistance slot (9), connected to the metal ground (2). 2. The three-polarization slot antenna with coplanar waveguide feeding capacitance loading step impedance according to claim 1, characterized in that the thickness, permeability and dielectric of the dielectric substrate (1) are changed constant, 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 working frequency and high The working frequency of the frequency working frequency band. 3. The three-polarized slot antenna with coplanar waveguide feeding capacitance loaded with step impedance according to claim 1, characterized in that the length of the low-resistance slot (8), the low-resistance slot (8) In the position in the radiation slot (3), the electrical length of the radiation slot (3) can be adjusted to achieve different degrees of miniaturization of the antenna, and the working frequency and high frequency of the antenna's low-frequency working frequency band can also be changed The operating frequency of the band. 4. The three-polarized slot antenna with a coplanar waveguide feeding capacitance loaded with step impedance according to claim 1, characterized in that the adjacent grid slots (6) in the array of grid slots (6) are changed The distance between the spacing, the width of the grid slit (6), the distance between the short-circuited end of the grid slit (6) and the radiation slot (3), can change the operating frequency of the antenna, the width of the working frequency band and the electrical length of the radiation slot (3). 5. The three-polarization slot antenna of a coplanar waveguide feeding capacitance loaded step impedance with grid slot ground according to claim 1, characterized in that changing the quantity, capacitance and spacing of the loading capacitor (7) can The characteristic impedance of the low-resistance slot (8) is adjusted to change the high-to-low impedance ratio of the step impedance radiation slot (3), thereby changing the working frequency of the low-frequency working frequency band and the working frequency of the high-frequency working frequency band of the antenna. 6. The three-polarized slot antenna with coplanar waveguide feeding capacitance loaded with step impedance according to claim 1, characterized in that the width of the radiation slot (3) can be adjusted to adjust the low-resistance slot The characteristic impedance of the slot (8) and the high-resistance slot (9) changes the high-to-low impedance ratio of the step impedance radiation slot (3), thereby changing the working frequency of the low-frequency working frequency band and the working frequency of the high-frequency working frequency band of the antenna.