Disclosure of Invention
In view of the above, the present invention provides a microstrip miniaturized harmonic suppression equal division power divider based on an H-type defected ground artificial transmission line, which solves the problems of the wilkinson power divider in the prior art that the size is too large and the harmonic suppression function is not provided.
In order to achieve the purpose, the invention provides the following technical scheme:
a miniaturized harmonic suppression equal power divider based on H-shaped defected ground artificial transmission lines comprises a dielectric substrate (1); a metal microstrip is arranged on one surface of the dielectric substrate (1), and a metal grounding plate is arranged on the other surface; the metal microstrip includes: the device comprises a metal microstrip surface part, a signal input port microstrip line (2), a signal first output port microstrip line (3), a signal second output port microstrip line (4) and a patch isolation resistor (12) of two sections of H-shaped defected ground artificial transmission lines; every section H type defected ground artificial transmission line is bilateral symmetry structure, includes: the device comprises two sections of folding thin transmission lines (5), two sections of vertical short thin transmission lines (6), two sections of horizontal thin transmission lines (7), two sections of short rectangular open-circuit branch sections (8), two sections of vertical long thin transmission lines (9), one section of horizontal thick transmission line (10), two long rectangular open-circuit branch sections (11) and an H-shaped defected ground structure (13) etched on a metal grounding plate; (i.e. each section of H-shaped artificial transmission line only comprises one H-shaped defected ground structure, and because of two sections of H-shaped artificial transmission lines, the total number of H-shaped defected ground structures is two.)
One end of each section of the vertical short and thin transmission line (6) is connected with one end of a section of the folding thin transmission line (5), and the other end of the vertical short and thin transmission line is connected with a section of the short rectangular open circuit branch section (8) through a section of the horizontal thin transmission line (7); one end of each section of vertical long and thin transmission line (9) is connected with one end of one section of vertical short and thin transmission line (6), and the other end of each section of vertical long and thin transmission line is connected with one long rectangular open-circuit branch node (11) through one side of the horizontal thick transmission line (10); the two long rectangular open-circuit branch nodes (11) are connected through a section of horizontal thick transmission line 10;
the signal input port microstrip line (2) is respectively connected with the signal first output port microstrip line (3) and the signal second output port microstrip line (4) through two sections of H-shaped defected ground artificial transmission lines; one end of the patch isolation resistor (12) is connected to the joint of one section of the folding thin transmission line (5) and the signal first output port microstrip line (3), and the other end of the patch isolation resistor is connected to the joint of the other section of the folding thin transmission line (5) and the signal second output port microstrip line (4);
the signal input port microstrip line (2) is used for inputting radio frequency signals, and the signal first output port microstrip line (3) and the signal second output port microstrip line (4) are used for outputting radio frequency signals after being equally divided; the patch isolation resistor (12) is used for isolating signal transmission between the first signal output port microstrip line (3) and the second signal output port microstrip line (4), and prevents crosstalk of a reflected signal between the two signal output ports caused by impedance mismatching between the two signal output microstrip lines and an external port.
Furthermore, a 45-degree cutting angle is formed at one side of the first signal output port microstrip line (3) and one side of the second signal output port microstrip line (4), and two 45-degree cutting angles are formed at the connection position of the signal input port microstrip line (2) and the two sections of the thin folding transmission lines (5).
Furthermore, each section of H-shaped defected ground artificial transmission line is equivalent to a section of quarter-wavelength transmission line, and has equivalent characteristic impedance of 70.7 omega and 90-degree phase shift; the characteristic impedances of the signal input port microstrip line (2), the signal first output port microstrip line (3) and the signal second output port microstrip line (4) are all 50 omega; the resistance value of the patch isolation resistor (12) is 100 omega.
Furthermore, the size of the power divider is determined by the dielectric constant of the dielectric substrate and the thickness of the dielectric substrate.
The invention has the beneficial effects that: the invention uses H-shaped defected artificial transmission line to replace the traditional quarter-wave transmission line, thus realizing the reduction of the size of the power divider, which is only 42 percent of the size of the traditional power divider. Meanwhile, an H-shaped defect ground structure is adopted in the design of the artificial transmission line, so that the power divider has a very wide harmonic suppression frequency band and a good harmonic suppression effect. The power divider can be applied to a miniaturized radio frequency circuit, and can also improve the signal-to-noise ratio of a communication system.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the means of the instrumentalities and combinations particularly pointed out hereinafter.
Drawings
For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:
fig. 1 is a schematic diagram of a front metal microstrip structure of the power divider of the present invention.
Fig. 2 is a schematic diagram of a back metal ground structure of the power divider according to the present invention.
Fig. 3 is a schematic diagram of a front metal microstrip circuit structure of a section of H-type defected ground artificial transmission line.
FIG. 4 is a schematic diagram of a back metal structure of a section of H-type defected ground artificial transmission line.
FIG. 5 is an equivalent circuit diagram of a front metal microstrip circuit of an H-type defected ground artificial transmission line.
FIG. 6 is an equivalent circuit diagram of a back H-type defected ground structure of an H-type defected ground artificial transmission line.
Fig. 7 is a sample structure dimension diagram of an embodiment of the power divider of the present invention.
Fig. 8 is a schematic structural diagram of a conventional equant wilkinson power divider.
Fig. 9 is a graph comparing the S-parameter of an artificial transmission line with H-type defects with the S-parameter of a 70.7 Ω microstrip transmission line.
Fig. 10 is a simulation S-parameter graph of a sample of an embodiment of the power divider of the present invention.
Fig. 11 is a simulation graph of the signal amplitude difference and the phase difference between two output ends of a sample of the power divider according to the embodiment of the present invention.
Fig. 12 is a simulation diagram of the S parameter of a conventional equant wilkinson power divider.
Reference numerals: the microstrip line structure comprises a 1-dielectric substrate, a 2-signal input port microstrip line, a 3-signal first output port microstrip line, a 4-signal second output port microstrip line, a 5-folding thin transmission line, a 6-vertical short thin transmission line, a 7-horizontal thin transmission line, an 8-short rectangular open-circuit branch section, a 9-vertical long thin transmission line, a 10-horizontal thick transmission line, an 11-long rectangular open-circuit branch section, a 12-patch isolation resistor and a 13-H type defected ground structure.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.
Wherein the showings are for the purpose of illustrating the invention only and not for the purpose of limiting the same, and in which there is shown by way of illustration only and not in the drawings in which there is no intention to limit the invention thereto; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", etc., based on the orientation or positional relationship shown in the drawings, it is only for convenience of description and simplification of description, but it is not an indication or suggestion that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes, and are not to be construed as limiting the present invention, and the specific meaning of the terms may be understood by those skilled in the art according to specific situations.
Referring to fig. 1 to 12, fig. 1 is a miniaturized harmonic suppression equal power divider of an artificial transmission line based on H-type defects, which includes a dielectric substrate 1; a metal microstrip is arranged on one surface of the dielectric substrate 1, and a metal grounding plate is arranged on the other surface; the metal microstrip includes: the surface part of the metal microstrip of the two sections of H-shaped defected ground artificial transmission lines, a signal input port microstrip line 2, a signal first output port microstrip line 3, a signal second output port microstrip line 4 and a patch isolation resistor 12; the front and back of a section of H-type defected ground artificial transmission line are respectively shown in fig. 3 and 4, each section of H-type defected ground artificial transmission line is in a bilateral symmetry structure, and the H-type defected ground artificial transmission line comprises: two sections of folding thin transmission lines 5, two sections of vertical short thin transmission lines 6, two sections of horizontal thin transmission lines 7, two sections of short rectangular open-circuit stubs 8, two sections of vertical long thin transmission lines 9, one section of horizontal thick transmission line 10, two long rectangular open-circuit stubs 11, and an H-shaped defected ground structure 13 etched on the metal grounding plate as shown in FIG. 2.
One end of each section of the vertical short thin transmission line 6 is connected with one end of a section of the folding thin transmission line 5, and the other end of the vertical short thin transmission line is connected with a section of the short rectangular open-circuit branch section 8 through a section of the horizontal thin transmission line 7; one end of each section of vertical long and thin transmission line 9 is connected with one end of a section of vertical short and thin transmission line 6, and the other end is connected with a long rectangular open-circuit branch section 11 through one side of a horizontal thick transmission line 10; two long rectangular open-circuit branch sections 11 are connected through a section of horizontal thick transmission line 10. The signal input port microstrip line 2 is respectively connected with a signal first output port microstrip line 3 and a signal second output port microstrip line 4 through two sections of H-shaped defected ground artificial transmission lines; one end of the patch isolation resistor 12 is connected to the connection between one section of the folded thin transmission line 5 and the first signal output port microstrip line 3, and the other end is connected to the connection between the other section of the folded thin transmission line 5 and the second signal output port microstrip line 4.
The signal input port microstrip line 2 is used for inputting radio frequency signals, and the signal first output port microstrip line 3 and the signal second output port microstrip line 4 are used for outputting radio frequency signals after being equally divided; the patch isolation resistor 12 is used for isolating signal transmission between the first signal output port microstrip line 3 and the second signal output port microstrip line 4, and preventing crosstalk of a reflected signal between the two signal output ports caused by impedance mismatch between the two signal output microstrip lines and an external port.
Each section of H-defect artificial transmission line is equivalent to a section of quarter-wave transmission line with equivalent characteristic impedance of 70.7 omega and 90 deg. phase shift. Characteristic impedances of a signal input port microstrip line 2, a signal first output port microstrip line 3 and a signal second output port microstrip line 4 of the power divider are both 50 omega. The resistance of the patch isolation resistor is 100 omega.
The equivalent circuit diagram of the metal microstrip surface of each section of H-shaped defected ground artificial transmission line is shown in FIG. 5, and a section of folded thin transmission line 5 can be equivalent to a series inductor Ls1And two capacitors C connected in parallel to grounds1And Cs2(ii) a A vertical short thin transmission line 6 can be equivalent to a series inductance Ls2(ii) a One section of the horizontal thin transmission line 7 can be equivalent to a series inductor Ls3The short rectangular open-circuit branch section 8 can be equivalent to a ground capacitor Cs3The vertical long and thin transmission line 9 is equivalent to a series inductor Ls4The horizontal thick transmission line 10 can be equivalent to three inductors connected in series, including two Ls5And a Ls6. The long rectangular open-circuit branch 11 can be equivalent to a ground parallel capacitor Cs4. The capacitive coupling between the two long and thin vertical transmission lines 9 and the capacitive coupling between the two short and thin vertical transmission lines 6 can be respectively equivalent to a series capacitor Cp1And Cp2. To pairThe H-shaped defected ground structure 13 on the other surface of the dielectric substrate 1 is equivalent to providing a parallel LC resonant circuit, the equivalent circuit of which is shown in FIG. 6, so that each H-shaped defected ground structure 13 can be equivalent to an inductor LdgAnd a capacitor CdgAre connected in parallel.
By connecting the capacitors C in parallel to the grounds3And a series inductance Ls3Can be equivalent to a capacitor Css3By connecting capacitors C in parallel to grounds4And a series inductance Ls5Can be equivalent to a capacitor Css4。Css3And Css4Can be respectively calculated as
In the above formula, ω is the angular frequency corresponding to the working frequency point.
The total series inductance L of each segment of the H-type defected ground artificial transmission linetCan be calculated as:
Lt=2Ls1+2Ls2+2Ls4+Ls6
total parallel capacitance CtCan be calculated as:
Ct=2Cs1+2Cs2+2Css3+2Css4
the characteristic impedance of the entire artificial transmission line is calculated as:
the phase shift of each artificial transmission line can be calculated as:
the main transmission line of the artificial transmission line comprises two sections of folding thin transmission lines 5, two sections of vertical short thin transmission lines 6, two sections of vertical long thin transmission lines 9 and horizontal thick transmission lines 10, and has smaller line width compared with a 70.7 omega microstrip transmission line, so that the artificial transmission line has larger series inductance, and the short rectangular open-circuit branch sections 8 and the long rectangular open-circuit branch sections 11 loaded on the main transmission line provide ground parallel capacitance, so that the H-shaped defected artificial transmission line can obtain larger total inductance L per unit length than the traditional uniform transmission linetAnd total capacitance CtThe size is more compact while achieving the same characteristic impedance and electrical length.
In addition, the artificial transmission line has a good harmonic suppression effect while achieving a compact size. Because the short rectangular open-circuit branch knot 8 and the horizontal thin transmission line 7 are cascaded, and the long rectangular open-circuit branch knot 11 and the horizontal thick transmission line 10 are cascaded to form the LC series resonance circuit on the parallel branch circuit, a transmission zero point can be introduced outside the passband of the transmission line, and the transmission line obtains the suppression effect on harmonic signals outside the passband. Secondly, because the H-shaped defected ground structure etched on the metal grounding plate has the band elimination characteristic, the equivalent circuit of the H-shaped defected ground structure is equivalent to an LC parallel circuit, a new transmission zero point can be introduced outside the transmission line passband, and the H-shaped defected ground structure is used for improving the stopband performance under the condition of not increasing the circuit size of the transmission line, so that the transmission line obtains better harmonic suppression performance.
Example (b):
the sample of the embodiment is a miniaturized harmonic suppression equal-division power divider of an H-shaped defect-based artificial transmission line with the working frequency of 0.9 GHz. The microstrip circuit of the sample of this example was etched on one side of a teflon dielectric substrate and the H-shaped defect was etched on the ground plane on the other side of the dielectric substrate. The dielectric substrate has a relative dielectric constant of ∈r2.65, the substrate thickness is 1 mm. The isolation resistor used in the sample of this example was a 0805 chip resistor having an impedance value of 100 Ω and a size of 2.0mm × 1.2 mm.
The circuit size of the power divider of the sample of this example was 17.7mm × 33.1 mm. I.e. 0.78 lambdag×0.15λg,λgThe guided wave wavelength on the dielectric substrate corresponding to the operating frequency of 0.9GHz is shown in fig. 7. As shown in fig. 8, in the case of using the same dielectric substrate and the same center operating frequency as the sample of the embodiment, the size of the conventional wilkinson power divider is 46.5mm × 30.0mm, and it can be seen that the sample of the embodiment has the size of only 42% of the conventional wilkinson power divider in fig. 8.
The dimension of the miniaturized harmonic suppression equal power divider of the artificial transmission line based on the H-type defect is marked as shown in FIG. 7, and the specific values of the marked dimension are shown in Table 1:
TABLE 1 actual values of the dimensions (unit: mm) of the samples of the examples are noted
Compared with the traditional 70.7 omega uniform microstrip transmission line, the H-shaped defected ground artificial transmission line has obvious suppression effect on harmonic signals outside the passband, as shown in figure 9.
An electromagnetic simulation software Zeland IE3D is used for simulating the miniaturized harmonic suppression equal power divider of the artificial transmission line based on the H-type defect of the sample of the embodiment of the invention, and the obtained simulation S parameter is shown in FIG. 10. I S11And | is the module value of the reflection coefficient of the signal input end. I S21I and I S31And | is a modulus of transmission coefficient of the signal from the port 1 of the power divider to the port 2 and the port 3 respectively. I S32And | is the modulus of the transmission coefficient of the signal from port 2 to port 3.
The simulation result shows that the working frequency point of the sample of the embodiment is 0.9 GHz. When | S11The example sample bandwidth ranges from 0.23GHz to 1.13GHz with 100% relative bandwidth when | is less than-10 dB. At the working frequency point of 0.9GHz, the | S thereof11The | is-27.5 dB, showing that the signal input port of the sample of this embodiment has good impedance matching.| S at this frequency point21I and I S31All the | are-3.2 dB, which shows that the loss of the signal at the working frequency point is very low and the good equal division effect is realized. Further, the | S' of the sample of this example over the operating bandwidth21I and I S31All is greater than-3.6 dB, which shows that the sample of the embodiment can achieve good signal equal division effect in the whole bandwidth range and keep the characteristic of low loss. And | S of the sample of this example in the frequency band range of 2.2GHz to 10.2GHz21I and I S31All is less than-20 dB, so that the sample of the embodiment generates a wide stop band range for harmonic signals, prevents higher harmonic signals from entering a communication system in the frequency band, and is favorable for improving the signal-to-noise ratio of the communication system. The sample of the embodiment shows good harmonic suppression effect, which is the performance that the traditional Wilkinson power divider does not have.
The amplitude difference and phase difference of the output signals of the two signal output ports 2 and 3 of the sample of the embodiment are shown in fig. 11. The figure shows that in the range of the bandwidth of 0.2GHz-1.3GHz, the amplitude difference between the output signals of the signal output port 3 and the signal output port 2 is less than 0.005dB, and the phase difference between the two output signals is less than 0.05 degrees, which indicates that the sample of the embodiment well realizes the constant-amplitude in-phase output of the signals in the range of the working bandwidth.
Fig. 12 is a simulation diagram of the S-parameter of a conventional power divider also operating at 0.9GHz operating frequency. As can be seen from fig. 12, the conventional power divider has a plurality of periodic harmonic passbands outside the bandwidth, and harmonic signals can enter the communication system through the passbands.
The invention can be known by combining the attached drawings and analysis, and the miniaturized harmonic suppression equal-division power divider of the artificial transmission line based on the H-shaped defects not only realizes the obvious size miniaturization effect, but also realizes the extremely wide harmonic stop band range and shows the good harmonic suppression effect, and the size of the power divider is only 42% of the traditional size. The power divider can be applied to a miniaturized radio frequency circuit, and can also improve the signal-to-noise ratio of a communication system.
Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.