CN105140645A - Harmonic suppressing antenna - Google Patents

Abstract

The invention provides a harmonic suppressing antenna. The harmonic suppressing antenna comprises an antenna and a filter; the antenna and the filter are connected through a metal probe; the filter feeds through a coaxial line; the antenna comprises an antenna patch and an antenna dielectric plate; the filter comprises a filter dielectric plate and a filter patch; a metal floor is arranged between the antenna dielectric plate and the filter dielectric plate; the filter patch comprises a phase-step impedance resonant unit, input and output microstrip lines at the two ends of the phase-step impedance resonant unit, and an open-circuit branch section in the middle of the phase-step impedance resonant unit; and each short-circuit branch section is provided with a grounded probe. The harmonic suppressing antenna, by introducing the phase-step impedance resonant unit, the open-circuit branch section and the short-circuit branch section, realizes the ultra-wide upper stop-band band-pass filter; the output end of the filter is connected with a conventional microstrip antenna, and the antenna with harmonic suppression of 10 times or more is obtained; compared with the conventional microstrip antenna, the harmonic gain of the harmonic suppressing antenna is reduced by more than 10 dB; and meanwhile, the gain, the axial ratio and other performances in the center frequency position of the harmonic suppressing antenna are not changed.

Description

Harmonic suppression antenna

technical field

The invention relates to the field of electronic technology, in particular to a harmonic suppression antenna with the capability of suppressing harmonics of more than 10th order.

Background technique

Antennas are indispensable components in modern microwave communication systems. Since the antenna front end often contains nonlinear devices such as amplifiers and mixers, a large number of harmonic components will be generated. If the antenna does not have the function of harmonic suppression, the harmonic energy will be emitted through the antenna, which will cause serious electromagnetic interference; or the harmonic energy will enter the system through the receiving antenna, causing system performance to deteriorate.

With the development of modern electronic technology, researchers have proposed some solutions to the above problems. It is divided into two categories in terms of methods: one is to design a filter with an ultra-wide upper stop band to filter out harmonic energy and then cascade the antenna; the other is to integrate the filter and antenna in the structure so that the structure can radiate energy At the same time play a role in filtering out harmonic energy. The advantage of the first method is that the antenna and filter can be designed independently, but the introduction of the filter is often accompanied by a large insertion loss, which reduces the gain of the antenna. At the same time, since the input impedance of the antenna is a frequency response function, the performance of the filter will be greatly reduced after the antenna is cascaded with the filter, which becomes the main technical challenge of the method, so the design of the method has not been reported in the public literature; the second One method is to integrate the filter and the antenna in the structural design so that the radiation structure has filtering performance at the same time. The advantage is that the systemic insertion loss can be reduced through structural interoperability. However, this method also has obvious difficulties. On the one hand, this method cannot achieve any number of harmonic suppression; radiation efficiency. So far, this method has been reported to have the best results in the design published in the 2014 article: "AModifiedCPW-FedSlotDipoleAntennaWithWidebandHarmonicSuppression", its harmonic suppression ability can reach 10dB suppression of the 2nd to 9th harmonic. But the radiation efficiency of its main polarization drops obviously, compared with the slot dipole antenna, the efficiency drops from 86% to 77%.

Contents of the invention

The object of the present invention is to overcome the disadvantages and deficiencies in the prior art, and propose an antenna with simple structure, convenient feeding, easy fabrication, and a harmonic suppression capability of more than 10 dB above 10.

Technical scheme of the present invention is as follows:

A kind of harmonic suppression antenna, comprising antenna, filter, described antenna and filter are connected through metal probe, and described filter is fed through coaxial line; Described antenna comprises antenna patch, the antenna below antenna patch A dielectric plate, the filter includes a filter dielectric plate, a filter patch below the filter dielectric plate, a metal floor is between the antenna dielectric plate and the filter dielectric plate, and the filter patch includes a step The impedance resonance unit, the input and output microstrip lines and short-circuit branches at both ends of the step impedance resonance unit, the open-circuit branch located in the middle of the step impedance resonance unit, and each short-circuit branch is provided with a grounding probe.

As a preferred manner, four open-circuit branches are arranged on the input microstrip line of the filter.

As a preferred mode, the width W0=3.12mm of the input microstrip line, the width W1=1mm of the short-circuit branch at both ends of the step impedance resonance unit, the low impedance width W2=4.8mm of the step impedance resonance unit, and the step impedance resonance unit The high impedance width W3=0.3mm, the width of the open branch in the middle of the step impedance resonance unit is respectively W4=5mm, W5=0.3mm, the length of the short circuit branch at both ends of the step impedance resonance unit L1=14mm, the step The low impedance length L2 of the impedance resonance unit=14mm, the high impedance length L3=18.2mm of the step impedance resonance unit, the lengths of the open-circuit branches in the middle of the step impedance resonance unit are respectively L4=10.5mm, L5=10mm; the input microstrip The lengths of the four open-circuit branches on the line are L6=8mm, L7=5.5mm, L8=3.8mm, and L9=2.7mm.

As a preferred manner, the antenna realizes left-handed circular polarization by cutting or sticking a block at a corner of the antenna patch.

As a preferred manner, the side length of the antenna patch is half the wavelength at the center frequency of the antenna.

As a preferred manner, the size of the metal floor is ag=bg=75mm, the size of the antenna dielectric plate is a=b=40mm, the size of the antenna patch is ap=bp=28.25mm, and the square size of the cut or pasted antenna patch is aq=bq = 3.3 mm.

As a preferred manner, the metal probes are respectively d1=5.0mm and d2=14.1mm away from the edge of the antenna patch.

The step impedance resonant unit (SIR) is the main resonant structure, and the input and output are composed of microstrip lines at both ends of the low impedance line. Several short-circuit branches are introduced into the low impedance line of the SIR, and a step impedance characteristic is introduced into the high impedance line of the SIR. The open branch of the branch; the energy is first fed to the filter through the 50 ohm coaxial line, and the ultra-wide upper stop band of the filter filters out the energy of the 2nd to 10th harmonics, and only allows the fundamental wave energy to pass through, followed by the The metal probe feeds the energy at the output of the filter to the antenna, so that only the fundamental wave energy is transmitted through the antenna, and the same is true for the energy received by the antenna.

The beneficial effect of the present invention is: by introducing step impedance resonant element (SIR) and open circuit, short-circuit branch realize ultra-wide upper stopband band-pass filter, and then connect traditional microstrip antenna at filter output terminal, obtain reaching 10 Compared with the traditional microstrip antenna, the harmonic gain of the antenna with sub-or even higher harmonic suppression is reduced by more than 10dB, while the gain at the center frequency and the performance of the axial ratio remain unchanged as a whole.

Description of drawings

Fig. 1 (a) is the top view of the present invention;

Fig. 1 (b) is the side view of the present invention;

Fig. 1 (c) is the bottom view of the present invention;

Fig. 2 is the simulation comparison diagram of the reflection coefficient of the embodiment of the present invention and traditional microstrip antenna;

Fig. 3 is the comparison diagram of gain simulation of the embodiment of the present invention and traditional microstrip antenna;

Fig. 4 is a schematic diagram of axial ratio simulation of an embodiment of the present invention;

FIG. 5 is a schematic diagram of radiation efficiency simulation according to an embodiment of the present invention;

FIG. 6 is a schematic diagram of a simulation of a polarization gain pattern according to an embodiment of the present invention.

1 is the metal floor, 2 is the antenna dielectric plate, 3 is the antenna patch, 4 is the metal probe, 5 is the filter dielectric plate, 6 is the filter patch, 7 is the ground probe, 61 is the step impedance resonance unit , 62 is a short circuit branch, 63 is an open circuit branch, and 8 is an input microstrip line.

Detailed ways

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention.

A kind of harmonic suppression antenna, comprising antenna, filter, described antenna and filter are connected through metal probe 4, and described filter is fed through coaxial line; Described antenna comprises antenna patch 3, below antenna patch The antenna dielectric board 2, the filter includes a filter dielectric board 5, the filter patch 6 below the filter dielectric board 5, the metal floor 1 is between the antenna dielectric board 2 and the filter dielectric board 5, so The filter patch 6 includes a step impedance resonance unit 61, input and output microstrip lines and short-circuit branches 62 at both ends of the step impedance resonance unit 61, and an open circuit branch 63 located in the middle of the step impedance resonance unit 61, each Each short-circuit branch is provided with a grounding probe 7 .

Four open-circuit branches 63 are provided on the input microstrip line 8 of the filter.

Specifically, in this embodiment, the width W0 of the input microstrip line is 3.12mm, the width of the short-circuit branch at both ends of the step impedance resonance unit is W1=1mm, and the low impedance width W2 of the step impedance resonance unit is 4.8mm. The high impedance width W3=0.3mm of the step impedance resonance unit, the width of the open circuit branch in the middle of the step impedance resonance unit is respectively W4=5mm, W5=0.3mm, the length L1 of the short circuit branch at both ends of the step impedance resonance unit= 14mm, the low impedance length L2 of the step impedance resonance unit=14mm, the high impedance length L3=18.2mm of the step impedance resonance unit, the lengths of the open-circuit branches in the middle of the step impedance resonance unit are respectively L4=10.5mm, L5= 10mm, the two open-circuit branches can be interchanged up and down without affecting performance.

The lengths of the four open-circuit branches on the input microstrip line 8 are L6=8mm, L7=5.5mm, L8=3.8mm, and L9=2.7mm. The order of the 4 open-circuit branches can be arranged arbitrarily without affecting the performance.

The size of the metal floor is ag=bg=75mm, the size of the antenna dielectric plate is a=b=40mm, the size of the antenna patch is ap=bp=28.25mm, and the square size of the cut or pasted antenna patch is aq=bq=3.3mm.

The metal probes 4 are respectively d1=5.0mm and d2=14.1mm from the edge of the antenna patch.

The antenna achieves left-handed circular polarization by cutting or sticking a block at a corner of the antenna patch. The side length of the antenna patch is half the wavelength at the center frequency of the antenna.

The step impedance resonant unit (SIR) is the main resonant structure, and the input and output are composed of microstrip lines at both ends of the low impedance line. Several short-circuit branches are introduced into the low impedance line of the SIR, and a step impedance characteristic is introduced into the high impedance line of the SIR. The open branch of the branch; the energy is first fed to the filter through the 50 ohm coaxial line, and the ultra-wide upper stop band of the filter filters out the energy of the 2nd to 10th harmonics, and only allows the fundamental wave energy to pass through, followed by the The metal probe feeds the energy at the output of the filter to the antenna, so that only the fundamental wave energy is transmitted through the antenna, and the same is true for the energy received by the antenna.

The present invention realizes an ultra-wide upper stopband bandpass filter by introducing a step impedance resonant unit (SIR) and open and short-circuit branches, and then connects a traditional microstrip antenna at the output end of the filter to obtain 10 or even higher orders The antenna with harmonic suppression, compared with the traditional microstrip antenna, the harmonic gain is reduced by more than 10dB, while the gain at the center frequency, the axial ratio and other performances remain unchanged as a whole.

The reflection coefficient comparison between the harmonic suppression antenna of this embodiment and the traditional microstrip antenna with the same index and size is shown in Figure 2. The traditional microstrip antenna has energy entering the antenna at many frequencies other than the center frequency. The energy entering at the point is still relatively large, and the reflection coefficient of this embodiment is close to -28dB at the center frequency, which is a good match, while the reflection coefficient up to the 10th harmonic outside the center frequency is close to 0dB, and the energy is basically completely reflected back .

The normal gain comparison between the harmonic suppression antenna of this embodiment and the traditional microstrip antenna is shown in Figure 3. The out-of-band gain of the traditional microstrip antenna is not well suppressed, and the gain at some frequency points is even higher than that of the center frequency The place is still large, and the harmonic suppression antenna solves this problem very well. The gain at the center frequency remains basically unchanged, but the harmonic gain drops by more than 10dB.

The axial ratio of the harmonic suppression antenna of this embodiment is shown in FIG. 4 , the axial ratio is less than 1 dB at the center frequency, and the circular polarization performance is good.

The radiation efficiency of the harmonic suppression antenna of this embodiment is shown in FIG. 5 , the radiation efficiency at the center frequency is about 82%, and the radiation performance of the antenna is good.

The polarization gain pattern of the harmonic suppression antenna of this embodiment is shown in FIG. 6 . In the normal direction at the center frequency, the gain of left-handed circular polarization is 25 dB greater than that of right-handed circular polarization, and the performance of left-handed circular polarization is good.

It can be seen from the simulation results that the embodiment antenna achieves single-feed left-handed circular polarization performance and broadband suppression up to the 10th harmonic by connecting a filter with an ultra-wide upper stop band to the traditional microstrip antenna.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (7)

1. a harmonics restraint antenna, is characterized in that: comprise antenna, filter, and described antenna is connected by metal probe with filter, and described filter passes through coaxial feeding; Described antenna comprises the antenna medium plate below antenna patch, antenna patch, described filter comprises the filter paster below filter medium plate, filter medium plate, be metal floor between described antenna medium plate and filter medium plate, described filter paster comprises a Stepped Impedance resonant element, the input and output microstrip line at Stepped Impedance resonant element two ends and short branch, be positioned at Stepped Impedance resonant element in the middle of open circuit detail, each short branch is respectively provided with a grounded probe.

2. harmonics restraint antenna according to claim 1, is characterized in that: the input microstrip line of filter is provided with 4 open circuit details.

3. harmonics restraint antenna according to claim 2, it is characterized in that: the width W 0=3.12mm of input microstrip line, the width W 1=1mm of the short branch at Stepped Impedance resonant element two ends, the Low ESR width W 2=4.8mm of Stepped Impedance resonant element, the high impedance width W 3=0.3mm of Stepped Impedance resonant element, the width of the open circuit detail in the middle of Stepped Impedance resonant element is respectively W4=5mm, W5=0.3mm, the length L1=14mm of the short branch at Stepped Impedance resonant element two ends, the Low ESR length L2=14mm of Stepped Impedance resonant element, the high impedance length L3=18.2mm of Stepped Impedance resonant element, the length L4=10.5mm respectively of the open circuit detail in the middle of Stepped Impedance resonant element, L5=10mm, the length of 4 open circuit details on input microstrip line is respectively L6=8mm, L7=5.5mm, L8=3.8mm, L9=2.7mm.

4. the harmonics restraint antenna according to claim 1 or 2 or 3, is characterized in that: described antenna is by realizing left-hand circular polarization at described antenna patch one clipped corner or stickup one square.

5. harmonics restraint antenna according to claim 1, is characterized in that: the length of side of described antenna patch is the half-wavelength at center of antenna frequency place.

6. harmonics restraint antenna according to claim 4, it is characterized in that: the size ag=bg=75mm of described metal floor, the size a=b=40mm of antenna medium plate, antenna patch size ap=bp=28.25mm, antenna patch excision or the block sizes aq=bq=3.3mm pasted.

7. harmonics restraint antenna according to claim 1, is characterized in that: described metal probe distance antenna patch edge is respectively d1=5.0mm, d2=14.1mm.