KR100700670B1 - Microstrip Split Ring Resonator - Google Patents

Abstract

The present invention relates to a microstrip split ring resonator which improves the quality, selectivity and size of the resonator by increasing the coupling strength due to the gap and slit of the signal line due to the novel structure of the microstrip split ring resonator.

The present invention provides a compact resonator structure that forms an internal gap between an open slit and a microstrip signal line extending a length of a microstrip signal line in a split ring resonator, and a capacitance due to an open slit and a distribution capacitance according to an internal gap. Equivalent correction capacity is maximized.

Capacitance by the open slit of the first microstrip signal line by the first or second microstrip signal line bent by H and by the open slit of the second microstrip signal line and the first and second microstrip signal lines Including the distribution capacitance due to the internal gap between the lines and by maximizing the equivalent capacitance by the capacitance and the distribution capacitance to minimize the size of the resonator.

Accordingly, the present invention provides an ultra-small microstrip split ring resonator having improved coupling efficiency by improving the capacitance and the equivalent capacitance of distributed capacitance by the novel structure of the split resonator, thereby improving the quality and selectivity of the resonator. In addition, it is effective in filters, duplexes, oscillators, mixers, and the like in microwave and millimeter wave circuits.

Resonator, elliptic function filter, coupling coefficient, attenuation pole, transfer zero, split ring resonator, bandpass filter, microstrip

Description

Microstrip Split Ring Resonator

1 is a structural diagram of a conventional open loop resonator

2 is a structural diagram of a conventional split ring resonator

3 is a structural diagram of a micro strip split ring resonator according to the present invention;

Figures 4a to 4c is an equivalent circuit diagram of a micro strip split ring resonator according to the present invention

5 is an elliptic function four-stage bandpass filter structure diagram using a microstrip split ring resonator according to the present invention

6 is an elliptic function four-stage bandpass filter graph using a microstrip split ring resonator according to the present invention.

7 is an elliptic function three-stage bandpass filter structure using a microstrip split ring resonator according to the present invention

8 is an elliptic function three-stage bandpass filter graph using a microstrip split ring resonator according to the present invention.

9 is an elliptic function four-stage bandpass filter structure diagram using a split ring resonator according to the present invention

10 is an elliptic function four-stage bandpass filter graph using a split ring resonator according to the present invention.

11 is an elliptic function three-stage bandpass filter structure diagram using a split ring resonator according to the present invention

12 is an elliptic function three stage band pass filter graph using a split ring resonator according to the present invention.

Explanation of symbols of the main parts of the drawings

10: microstrip signal line

11, 13: first micro strip signal line

12, 14: second micro strip signal line

20: micro strip coupling slit

21: first micro strip coupling slit

22: second microstrip coupling slit

30, 31: internal gap 32: internal space

40: open slit of the first microstrip signal line

41: closed slit of the first microstrip signal line

50: open slit of second microstrip signal line

60, 70, 80, 90: first interval 61, 71, 81, 91: second interval

62, 82: third interval 100, 500, 800, 1200: first resonator

110, 510, 810, 1210: input line

200, 600, 900, 1300: second resonator

300, 700, 1000, 1400: third resonator

400, 1100: fourth resonator 410, 710, 1110, 1410: output line

The present invention relates to a microstrip split ring resonator, and more particularly, to increase the coupling strength by the gap and slit of the signal line due to the novel structure of the microstrip split ring resonator. A microstrip split ring resonator with improved selectivity and size.

1 is a schematic diagram of a conventional open loop resonator, wherein the open loop resonator is a structure in which one side of the microstrip signal line 10 is formed of a microstrip coupling slit 20 and bent in a square shape, and FIG. As the ring resonator structure diagram, the split ring resonator has a second microstrip signal line 12 having the same structure inside the first microstrip signal line 11 having a first micro strip coupling slit 21 formed in a rectangular curved structure. ) Inserting and inserting the first and second micro strip coupling slits 21 and 22 in opposite directions to each other, the internal gap between the first and second micro strip signal lines 11 and 12. 30) is formed.

As described above, the resonators determine the coupling efficiency by the inner gap 30. When the size of the inner gap 30 is small, the coupling effect is increased, and when the size of the gap is increased, the coupling effect is also reduced. Therefore, the coupling structure has a problem in that it is difficult to improve the quality and selectivity of the resonator because there is a process limitation in reducing the size of the inner gap 30.

As another conventional resonator, there is a hairpin resonator using a micro strip, and the hairpin resonator has a low loss compared to the dielectric resonator DR and can be used in a higher frequency region compared to a structure having a lumped element capacitor. In addition, because the length of the parallel coupling line (trimming) can be tuned and the frequency can be tuned, and because of the planar structure, there was a resonator that can easily implement MIC (Microwave Integrated Circuit) and MMIC (Monolithic Microwave Integrated Circuit).

Conventional hairpin resonator has reached the limit to increase the coupling strength (Coupling Strength), and there was a technique of controlling the properties of the substrate (Substrate) as a workaround, but without the increase in the strength of the fundamental cupping Due to the inability to use the same high frequency, there was an inevitable problem of mass production of expensive products.

Accordingly, an object of the present invention is to provide a microstrip split ring resonator with increased coupling strength and improved quality, selectivity, and size of a fundamental resonator.

The microstrip split ring resonator according to an embodiment of the present invention for achieving the above object and the H-shaped first microstrip signal line formed with a first open slit portion at one side end, and a closed slit portion at the other side end; A first open type H-shaped second micro strip signal line having a constant internal gap with the H-shaped first micro strip signal line and formed along an H-shaped bent shape and the second H-shaped micro strip signal line; A second open slit portion is formed in a direction opposite to the slit portion.
According to an embodiment of the present invention, the first micro strip signal line and the second micro strip signal line are characterized in that the coupling strength is increased by the first and second open slit portions or the internal gap.
According to an embodiment of the present invention, the equivalent capacitance is maximized by the capacitance by the first and second open slit portions of the first and second micro strip signal lines and the distribution capacitance by the internal gap. It is characterized by.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a structural diagram of a micro strip split ring resonator according to the present invention, wherein the split ring resonator has a meander line structure. That is, the open slit 40 of the first micro strip signal line is formed and the closed slit 41 of the first micro strip signal line is formed on the other side of the open slit 40 of the first micro strip signal line. The first micro strip signal line 13 bent in an H shape and the internal gap 31 are reduced by a predetermined ratio based on the first micro strip signal line 13 in the first micro strip signal line 13. A second microstrip bent in H so that an internal space 32 is formed and an open slit 50 of the second microstrip signal line is formed in a direction opposite to the open slit 40 of the first microstrip signal line. It consists of a signal line 12.

First, in order to describe the microstrip split ring resonator, a conventional split ring resonator will be described with reference to FIGS. 2 or 4A to 4C. The first microstrip signal line 11 and the second microstrip signal line 12 will be described. 4B to 4C are represented by R, L and C equivalent circuits, the application of the signal on the input line is represented by the signal power of the first microstrip signal line 11 and the equivalent signal voltage source is It is excited by two microstrip signal lines 12, where the second microstrip signal line 12 also appears as an equivalent signal voltage source relative to the first microstrip signal line 11. Accordingly, as shown in FIG. 4B, the total equivalent signal voltage source of the resonator considering both equivalent signal voltage sources on the first microstrip signal line 11 and the second microstrip signal line 12 is represented by the following Faraday law. faraday's law).

V = -jωμ ₀ AH _i

V: Induced Voltage Source

ω: radial frequency

H _i : Incident magnetic field

A: loop area

μ ₀ : free-space permeability

Thus, as shown in FIG. 4A or 4B, A of the second microstrip signal line 12 is modeled as an equivalent signal voltage source V _o and B of the second microstrip signal line 12 is an equivalent signal voltage source V _i. Is modeled as: In addition, symbols R ' and L' are distributed resistance and distributed inductance, C _slit is capacitance of the slits, and C ' is the first and second two. The distributed capacitance of the internal gap 30 between the micro strip signal lines 11 and 12.

The frequency signal input to the input feed line line flows from the first micro strip signal line 12 to the second micro strip signal line 12 through the internal gap 30. At this time, the value of the equivalent voltage source is relatively different between the first microstrip signal line 11 and the second microstrip signal line 12 according to their positions. That is, as shown in FIG. 4A, the minimum value increases toward the slit direction of the signal line, and the maximum value occurs at the center points A and B, respectively.

4C, which is a simplified circuit diagram of FIG. 4B, is omitted since the equivalent capacitance through the slit of the equivalent circuit diagram of FIG. 4B has a smaller value than the equivalent capacitance of the inner gap 30. Therefore, it can be simplified by the RLC serial tank circuit shown in Figure 4c.

On the other hand, since the arrangement of the first and second micro strip signal lines 11 and 12 is symmetrical with each other, as shown in FIG. 4A, the upper portion of the first micro strip signal line 11 has a negative charge value. The upper portion of the second microstrip signal line 12 has a relatively positive induced charge. This phenomenon is consistent with the lower part of the first or second microstrip signal lines 11 and 12.

Therefore, based on the equivalent circuit diagram, the resonant frequency of the resonator is simplified by the following formula.

ω ₀ = sqrt (2 / pLC _pul )

ω ₀ : resonance frequency

C _{pu l} : capacitance per unit length for internal gap

L: Total inductance for the entire first and second microstrip signal lines

r ₀ : average radius between the first and second microstrip signal lines

As a result, the microstrip split ring resonator of the present invention is almost the same as the signal flow of FIGS. 4A to 4C, but the structure of the first and second microstrip signal lines of FIG. 2 is bent in H shape as shown in FIG. By fabrication, the open slit 40 of the first microstrip signal line by the first or second micro signal lines 13 and 14 and the capacitance by the open slit 50 of the second microstrip signal line and the first Including the distribution capacitance by the internal gap 31 between the one microstrip signal line 13 and the second microstrip signal line 14, the capacitance and the distribution capacitance maximize the equivalent capacitance in terms of overall size. It is a much smaller form.

Accordingly, the present invention microstrip split ring resonator has an internal gap 31 between the first microstrip signal line 13 and the second microstrip signal line 14 or the slits of the first and second microstrip signal lines ( Due to the increase in the filling strength of 40 and 41), the resonant frequency of the resonator of the present invention has a very large low-frequency shift and greatly reduces the size of the resonator when designing the same center frequency.

In addition, the present invention microstrip split ring resonator has a thickness of 0.48 mm in each of the first and second microstrip signal lines 13 and 14, and the interior between the first and second microstrip signal lines 13 and 14. The gap 31 is set to 0.2 mm, the length of the longitudinal internal space 32 inside the second micro strip signal line 14 is 0.5 mm, and the width inside the second micro strip signal line 14. Most preferably, the longitudinal length of the directional internal space 32 is 0.56 mm.

5 is an elliptic function four-stage bandpass filter structure diagram using a microstrip split ring resonator according to the present invention, wherein the four-stage bandpass filter structure diagram shows four microstrip split ring resonators of FIG. For example, the four resonators are referred to as a first resonator 100, a second resonator 200, a third resonator 300, and a fourth resonator 400 for convenience. The filter of the present invention manufactured by arranging the four resonators 100, 200, 300, and 400 includes an open slit 40 of a first microstrip signal line formed in the first resonator 100 or the second resonator 200. Are arranged facing each other and spaced apart from the first resonator 100 and the second resonator 200 by a first interval 60.

Thereafter, the third resonator 300 and the fourth resonator 400 are arranged to be spaced apart by a second interval 61 from the lower end of the arranged first resonator 100 and the second resonator 200. In addition, in arranging the third resonator 300 and the fourth resonator 400, the third resonator 300 and the fourth resonator 400 may connect the closed slits 41 of the first microstrip signal line to each other. On the other hand, the filter is configured by arranging the third resonator 300 and the fourth resonator 400 to be spaced apart by a third interval 62. Meanwhile, the first resonator 110 becomes the input line 110 and the second resonator 200 becomes the output line 210.

The filters arranged as above are divided into four types of couplings in each resonance period. The first is Electrical Coupling. Coupling in this case is the coupling generated between the first resonator 100 and the second resonator 200, which is equivalent to the equivalent signal voltage source of the centers A and B of the signal lines of FIGS. 4A to 4C described above. As the electric field is large, the cut edge of the slit 40 has a large magnetic field. Therefore, the coupling between the sections where the electric force is strong is called electrical coupling.

Next, there is a magnetic coupling (coupling), which is a coupling between the magnetically strong parts as opposed to the electrical coupling. Therefore, this is called a magnetic coupling structure and is a coupling occurring between the third resonator 300 and the fourth resonator 400. In addition to the electrical coupling and the magnetic coupling, the two couplings may be referred to as a first mixed coupling I and a second mixed coupling II, and the first hybrid coupling may be referred to as a first resonator 100. ) And a third resonator 300 and a coupling structure between the second resonator 200 and the fourth resonator 400, and the second hybrid coupling is used in the three-stage structure shown in FIG. 7.

In addition, the amount of coupling intersecting between the first resonator 100, the fourth resonator 400, and the second resonator 200 and the third resonator 300 in a diagonal direction is canceled out and suppressed. In addition, the amount of each coupling decreases with increasing distance in the resonance period, and the value of this distance is based on the elliptic function filter theory, which has been studied previously. 10.03). This harmonization between these different couplings results in the final output of the filter, forming a transmission pole or attenuation zero in the adjacent frequency band of the passband, thus improving the quality factor of the filter.

The first interval 60, the second interval 61, and the third interval 62 are calculated based on the filter design conditions. The first interval 60 is 1.92 mm, and the second interval 61 is calculated. ) Is 1.61 mm, and the third gap 62 is most preferably manufactured at 1.67 mm.

Therefore, the elliptic function four-stage bandpass filter using the microstrip split ring resonator generates attenuation poles in both adjacent frequency bands of the passband, thereby improving the filter selectivity.

FIG. 6 is an elliptic function four-stage bandpass filter graph using a microstrip split ring resonator according to the present invention. First, S11 is a reflection loss and S21 is an insertion loss. The center frequency of, the 60MHz bandwidth (Factional Bandwidth), 2.63dB insertion loss, the return loss is designed to satisfy 26.10dB, and the measured value is the insertion loss and reflection at 2.0 한 with the center frequency slightly shifted from the simulation value. The loss is very similar to 4.28dB and 13.0dB. In addition, the skirt characteristic is improved by the influence of the attenuation poles in both adjacent frequency bands (f _o + 81.5 MHz) of the pass band.

7 is an elliptic function three-stage bandpass filter structure diagram using a microstrip split ring resonator according to the present invention, wherein the three-stage bandpass filter structure diagram shows three microstrip split ring resonators of FIG. The three resonators are referred to as a first resonator 500, a second resonator 600, and a third resonator 700 for convenience. The filter using the three resonators 500, 600, and 700 rotates the third resonator 700 by 90 degrees, and then spaces the second resonator 71 by about two intervals 71 to separate the first resonator 500 and the second resonator 600. The first resonator 500 and the second resonator 600 are arranged so that the open side surfaces of the microstrip coupling slip gap 40 formed in the resonator face each other at a first interval 70 to form a filter. The first resonator 500 becomes the input line 510 and the second resonator 600 becomes the output line 610. Unlike the four-stage bandpass filter, the first resonator 500 becomes an attenuation pole in the adjacent frequency band in the right high frequency band direction. This is a structure in which only one blocking characteristic is generated to be improved.

The first interval 70 and the second interval 71 are calculated based on the design conditions of the filter. The first interval 70 is preferably 0.91 mm and the second interval 71 is 0.55 mm.

The three-stage filter is composed of three resonators, and there are various coupling types as in the four-stage filter described above. First, an electrical coupling form exists between the first resonator 500 and the second resonator 600. Next, between the first resonator 500, the third resonator 700, the second resonator 600, and the third resonator 700, the second hybrid coupling (Mixed Coupling II) mentioned in the fourth stage is provided. exist. The second hybrid coupling has both an electrical coupling and a magnetic coupling at the same time, and most of the input signal is transmitted to the output through the second resonator 600 through the third resonator 700. At this time, although the coupling strength between the first resonator 500 and the second resonator 600 is relatively very weak, some of the main signal components are transmitted in the form of this hybrid coupling, thereby allowing the right side of the pass band of the filter to pass through. Poles are generated in the adjacent frequency band. Therefore, the Q value, which is a performance indicator of the filter, is much improved. In addition, such a three-stage filter structure is used to provide relatively superior blocking characteristics for one frequency band, such as a duplexer or triplexer. The filter structure is very small in size and superior in performance. Very effective.

8 is an elliptic function three-stage bandpass filter graph using a split ring resonator according to the present invention. First, S11 is a reflection loss, S21 is an insertion loss, and the three-stage bandpass graph has a center frequency of 1.95 Hz. The theoretical insertion loss and the return loss have a 1.36dB and 23.53dB, respectively, in the operational bandwidth of about 60MHz, and the measured values correspond to the insertion loss at 2.0㎓ with the center frequency slightly shifted from the simulation value. The return loss is very similar to 2.77dB and 12.3dB. In addition, attenuation poles are generated at frequencies that are about 13 MHz further moved (fo ± 78 MHz) than the design value in the right high frequency band of the passband, thereby improving the skirt characteristic.

9 is an elliptic function four-stage bandpass filter structure diagram using a split ring resonator according to an embodiment of the present invention. For convenience, the four resonators include a first resonator 800, a second resonator 900, a third resonator 1000, and a fourth resonator. Called the resonator 1100, the four resonator 800, 900, 1000, and 1100 arrays are the same as the arrangement shown in FIG. 4, with only a difference in spacing, and the first resonator 800 and the second resonator ( The first spacing 80 between 900 is 2.5 mm, the second spacing 81 between the first resonator 800 and the second resonator 900, and the third resonator 1000 and the fourth resonator 1100. Is 0.95 mm, and the third gap 82 between the third resonator 1000 and the fourth resonator 1100 is most preferably 2.4 mm.

The resonator arrangement method is the same as the arrangement structure shown in Fig. 5, and the difference in distance between the resonance periods, which is the difference between the arrangements, is due to the different coupling types. The electrical coupling between the first resonator 800 and the second resonator 900 is about 1/2 of the strength of the magnetic coupling between the third resonator 1000 and the fourth resonator 1100. The main input signal component is transferred to the output via the third resonator 1000 and the fourth resonator 1100. However, only a small amount of a very weak signal is transmitted from the first resonator 800 to the second resonator 900, thereby generating poles in both neighboring frequency bands of the pass band of the filter, thereby providing a Q value or selectivity of the filter. (Selectivity) can be improved. In addition, the distance between the resonance periods used here is determined by the strength of the coupling corresponding to the structure of each different coupling, and the strength of the coupling is the elliptic function filter theory that has been studied previously. Based on electromagnetic simulation (EM Simulation, IE3D ver. 10.03).

10 is a graph of an elliptic function four-stage bandpass filter using a split ring resonator according to the present invention. First, S11 is a reflection loss, S21 is an insertion loss, and the four-stage bandpass filter has a center frequency of 2.46 kHz, and In the 100MHz bandwidth, the insertion loss is 1.8dB and the return loss is 26.27dB, and the insertion loss is 2.63dB and 16.9dB. In addition, the effect of attenuation poles in the adjacent frequency bands (f ₀ ± 112 MHz) on both sides of the pass band improves the spacing and size significantly compared to the case of using the loop filter.

FIG. 11 is an elliptic function three-stage bandpass filter structure diagram using a split ring resonator according to the present invention. The arrangement of the three resonators 1200, 1300, and 1400 is the same as the arrangement shown in FIG. 7, and there is only a difference in the spacing, and the first resonator 1200, the second resonator 1300, and the third resonator 1400 are different from each other. The second spacing 91 therebetween is preferably 0.95 mm, and the first spacing 90 between the first resonator 1200 and the second resonator 1300 is preferably 1.21 mm.

It is the same as the arrangement shown in FIG. 7, and the second hybrid coupling, which was not used in the fourth stage, includes the first resonator 1200, the third resonator 1400, the second resonator 1300, and the third resonator 1400. By applying it to the coupling structure between), poles are formed in the frequency band near the right side of the pass band to improve selectivity and blocking characteristics.

11 is an elliptic function three-stage bandpass filter graph using a split ring resonator according to the present invention. First, S11 is a reflection loss, S21 is an insertion loss, and the three-stage bandpass filter has a center frequency of 2.46 kHz, and In the 100MHz bandwidth, the theoretical insertion loss and return loss are 0.885dB and 30.95dB respectively, and the measured values show that the insertion loss and return loss are 1.35dB and 16.8dB at 2.512㎓ with the center frequency slightly shifted from the simulation value. It has been proven to have very similar properties. In the high frequency band on the right side of the pass band, the attenuation pole is generated at a frequency shifted approximately 90 MHz (f _o ± 209 MHz), which improves the skirt characteristic. Slight frequency shifts in the measurements are inevitable errors due to process limitations in the manufacturing process.

 The best embodiments have been disclosed in the drawings and specification above. The specific terminology used herein is for the purpose of describing the present invention only and is not intended to be limiting of meaning or the scope of the invention as set forth in the claims. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from this. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, according to the present invention, the microstructured microstrip split improves the coupling efficiency by improving the coupling efficiency by increasing the capacitance and the equivalent capacitance of the distributed capacitance according to the novel structure of the split ring resonator. It has the effect of providing a ring resonator and is applied to filters, duplexes, oscillators, mixers, etc. in microwave and millimeter wave circuits.

Claims (9)

A first H-shaped microstrip signal line having a first open slit portion at one side end and a closed slit portion at the other side end; A second H-shaped micro strip signal line having a predetermined internal gap with the H-shaped first micro strip signal line and formed along an H-shaped bent shape; And And a second open slit portion in a direction opposite to the first open slit portion in the H-shaped second microstrip signal line. The microstrip split ring resonator as set forth in claim 1, wherein the first microstrip signal line and the second microstrip signal line are increased in coupling strength by first and second open slit portions or an internal gap. The method of claim 1, wherein the equivalent capacitance is maximized by the capacitance by the first and second open slit portions of the first micro strip signal line and the second micro strip signal line and the distribution capacitance by the internal gap. Micro strip split ring resonator. delete delete delete delete delete delete

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