KR101435246B1 - Broadening the Bandwidth and Improving the gain of the CRLH Zeroth Order Resonance Antenna in the form of a microstrip patch capacitively coupled with a ring mushroom - Google Patents

Abstract

The present invention is a new matte material CRLH resonance structure in which a single ring mushroom is connected to a general patch of an easy-to-coaxial feed type at a constant interval. The CRLH resonance structure is a flat, spherical low- profile antenna. First, a narrowband multi-band antenna including a zero-order resonance without phase change and a -1st order resonance with a phase-leading phenomenon is designed first, and then a -1st resonance point is shifted to the vicinity of the 0th order resonance point, Which is a disadvantage caused by the miniaturization of the meta material structure and has a high antenna gain and efficiency while having a monopole radiation pattern all over the band and extending from 3% to 30% And a method for enhancing the gain of the antenna.

Description

Technical Field [0001] The present invention relates to a CRLH zero resonant antenna and a capacitive coupled microstrip patch structure with a ring mushroom. }

In the present invention, the 0th order resonance and the -1st order resonance phenomenon based on the metamaterial complex right hand transmission and the left hand transmission (CRLH) structure occur, and the -1st order resonance point is shifted to the vicinity of the 0th order resonance to improve the bandwidth And a design of a planar antenna having a radiation pattern of a monopole antenna. Particularly, it is possible to provide a structure in which the electric field of the RF signal is made to have the same phase over the whole structure, not the positive integral multiples of half-wave resonance or half-wave resonance, which is the fundamental resonance mode of the general microstrip patch structure, Dimensional zero resonance antenna, which is periodically connected in series and has only one capacitive coupling ring mushroom around a metal patch, and has a first-order resonance characteristic And then the first-order resonance and the zero-order resonance points are gathered together to form a ring mushroom and a capacitively coupled microstrip patch structure that greatly enlarge the bandwidth. The CRLH 0th order resonant antenna is used to enhance the broadband and gain Antenna design.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a design part of a small antenna which is a core component of a small system configuration among RF (Microwave / Millimeter-wave) areas. In the conventional antenna design technique, the mushroom structure composed of the patch and the shorting pin is periodically connected to show the CRLH DNG (Double Negative) type 0th order resonance characteristic by the effective permittivity and the effective permeability of the negative. In addition to DNG, an antenna may be designed with an ENG (Epsilon Negative) structure having a negative effective permittivity and a positive effective permeability. However, this is also a periodic structure, and the antenna gain stays at a small value even as the size of the antenna increases. In addition, the mathematical material characteristics are obtained throughout the periodic structure, and there is also a disadvantage in that design freedom is lowered from repetition of fixed design variables.

Generally, the radiation of the electromagnetic wave in the horizontal direction is very weak in the conventional plane patch antenna. In other words, the monopole antenna that emits electromagnetic waves in the flat direction has a length of 1/4 wavelength, and the height is fixed, so it is not easy to make a low-profile. Conventional zero-order resonant antennas that emit electromagnetic waves in a horizontal direction with low-profile characteristics that solve the above two problems have narrow bandwidths of less than 10% of the bandwidth and very low antenna gains of one cell.

Accordingly, an object of the present invention is to provide a non-cylindrical type zero-order and first-order resonance antenna in which capacitive coupling occurs by adding a ring mushroom having a shorting pin to the outside of a simple microstrip patch, The positive resonance is shifted to the 0th order resonance by increasing the series capacitance value and the series inductance, respectively, thereby greatly expanding the bandwidth of the 0th order resonance and improving the antenna gain.

Planar Matte Material Structure of the Present Invention The CRLH antenna design is a DNG type 0th order resonant antenna that joins a ring mushroom having a short pin to an easy coaxial feed patch with a certain distance. It has a zero-order resonance characteristic, Can be seen.

Also, since the ring mushroom structure of the present invention clearly shows not only zero-order resonance characteristics but also -1st order resonance characteristics, it is necessary to set the -1st and positive resonance points to 0 It is a low-profile antenna with a monopole radiation pattern and a high gain with a bandwidth of 30% or more by moving to the vicinity of the resonance.

Also, in the antenna of the present invention, the size of the ring mushroom increases as the size of the patch decreases and the size of the patch increases while maintaining the overall size of the structure change for extending the bandwidth. The effect of decreasing the CL value due to the reduction of the contact area while having a constant coupling distance and the effect of increasing the LR value by increasing the ring width.

Accordingly, as the CL value decreases, the -1st order resonance frequency, which was lower than the 0th order resonance frequency, becomes higher and moves to the vicinity of the 0th order resonance frequency. When the LR value becomes larger, positive resonance frequencies higher than the 0th order resonance frequency become near the 0th order resonance The effect of expanding the band can be obtained.

The core technique for designing the antenna of the present invention is to reduce the series capacitance caused by the combination of the mushroom and the patch for the upward movement of the first-order resonance frequency. However, the area of the inner patch is reduced while maintaining the overall size, since the circumference of combining with a certain distance in effect reduced, reducing the series C (C _L) value, the series inductance L (L _R) is increased in the process of reducing the series C value to be increased for the downward movement of the resonance frequency of the pumping The increased inductance of the ring increases the width of the ring. Therefore, it is possible to obtain a small-sized planar antenna capable of emitting in a horizontal direction on a wide band.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a general metamaterial CRLH transmission line. FIG.
FIG. 2 is a diagram showing a periodic arrangement of mushroom structure unit cells in the prior art. FIG.
FIG. 3 is a view illustrating a general patch antenna using a coaxial feed, and is a central antenna for designing a target antenna.
4 is a ring mushroom structure including a shorting pin for making a proposed antenna in combination with a patch.
FIG. 5 is a view of a narrowband zero-order resonant antenna due to the combination of the structures shown in FIG. 3 and FIG.
6 is an antenna diagram showing an equivalent circuit for the structure of Fig.
FIG. 7 is a diagram of a zero order resonant antenna having a narrowband that includes a zero order resonance at 2.5 GHz and a -1st order of 2.04 GH.
FIG. 8 is a diagram showing S-parameter results between the antenna of FIG. 7 and simulations. FIG.
9 is a diagram showing a radiation pattern at 2.04 GHz, which is the -1 st order resonance point of the 0th order resonance antenna having a narrow band.
10 shows the electric field distribution at 2.04 GHz, which is the -1st-order resonance point of the 0th order resonance antenna having the narrow band.
11 is a diagram showing a radiation pattern at 2.5 GHz, which is a zero-order resonance point of a zero-order resonance antenna having a narrow band.
Fig. 12 is a view showing the electric field distribution at 2.5 GHz, which is the 0th-order resonance point of the 0th order resonance antenna having the narrow band.
Fig. 13 is a diagram for comparing simulation results and measurement results of the 0-order resonance antenna 2-D radiation pattern having a narrow band.
FIG. 14 is a diagram illustrating a process of bringing the center patch antenna unit small and increasing the width of the ring mushroom while maintaining the overall size of the zero-order resonance antenna of the narrow band by moving the -1st resonance point to make it wide.
FIG. 15 is a graph showing characteristics of an S parameter changed when the width of a ring mushroom according to FIG. 14 increases.
16 is a view showing a photograph of the fabrication of the broadband antenna of the present invention.
17 is a diagram showing S parameter results of the wideband antenna of the present invention.
18 is a view showing a radiation pattern of the broadband antenna of the present invention.
19 is a view showing an electric field distribution of a broadband antenna of the present invention.
20 is a diagram showing a radiation pattern result of a broadband antenna of the anti-invention invention.

In the design of antennas, the CRLH transmission line theory is used to design the antennas, which is one of the radiation characteristics of linear antennas and has monopole radiation characteristics and low-profile characteristics and miniaturization thereof. The way to use is emerging as an alternative.

Here, the matte material structure is an artificial material having a negative permittivity or negative permeability that does not exist as a natural substance at a specific frequency. When the transmission line is implemented, the right-handed (RH) (Left right) and left-handed (LH) characteristics. In this case, the combination of RH and LH is called a composite right and left handedness (CRLH).

The present invention will now be described in detail with reference to the drawings.

), C_R, L_L에 의해 병렬공진(

)이 일어나게 된다. 이 두 주파수가 서로 다를 경우에는 Unbalanced 형태로 Bandgap이 형성되어 차단 대역 특성이 나타나며 서로 같을 경우에는 balanced 형태가 된다.Fig. 1 shows a basic material structure CRLH transmission line. The CRLH transmission line consists of series L _R , C _L and parallel C _R, L _L. The series inductance (L _R ) and the parallel capacitance (C _R ) exhibit right-handed (RH) characteristics and the series capacitance (C _L ) and parallel inductance (L _L ) exhibit left-handed (LH) characteristics. The cut-off frequency is determined by the respective RH and LH characteristics, and a pass band is formed. Also, by LR and C _L , series resonance (

), C _R, L _L by parallel resonance (

). If the two frequencies are different, the unbalanced bandgap is formed and the blocking band characteristics are shown.

은 RH영역의

와 LH영역의

의 합에 의해 결정되며 LH영역의

이 음의 부호를 가지며 관련 수식은 다음과 같다.Also, the total phase velocity of the CRLH transmission line

Of the RH region

And LH regions

Lt; RTI ID = 0.0 > LH < / RTI &

This negative sign has the following formula.

[Equation 1]

&Quot; (2) "

&Quot; (3) "

&Quot; (4) "

&Quot; (5) "

이 0의 값을 가지게 되면 0차 공진이 발생하게 되고,

=0인 경우 파장이 무한대가 되고 전파 전송에 따른 위상지연이 발생하지 않는다. if

If this value is 0, the 0th order resonance occurs,

= 0, the wavelength becomes infinite and the phase delay due to the radio wave transmission does not occur.

For this reason, the phase is the same, so that the transmission line and the resonator have the same phase over the entirety. The resonance frequency of this mode does not depend on the length of the antenna since the reactance components constituting the CRLH transmission line are determined. Therefore, it is possible to form an electric field and a magnetic field having the same change irrespective of the physical length, which is a method of miniaturizing the parts and having new characteristics.

Further, there is a characteristic of having a monopole radiation characteristic of high efficiency at the 0th order resonance point.

In particular, a large magnetic current loop is generated as a single-cell type, not according to the conventional two-dimensional periodic array method, and the gain can be greatly improved even at the zero-order resonance.

In order to design the antenna by forming a single cell material structure CRLH transmission line, a series of capacitive coupling through a gap with a ring mushroom including a shorting pin is used, , 4 and 5, and the equivalent circuit for the structure can be confirmed in FIG.

FIG. 2 is a view showing a periodic arrangement of unit cells of a conventional mushroom structure, FIG. 3 is a view of a general patch antenna, and FIG. 4 is a ring mushroom structure connected to a ground through a shorting pin 203.

In FIG. 3, reference numeral 101 denotes a perspective view of the antenna, reference numeral 102 denotes a metal shape, and reference numeral 103 denotes coaxial feeding. Also in Fig. 4, 201 is a perspective view, and 202 is only a metal shape.

FIG. 7 is a photograph of an antenna designed and designed to have a zero-order resonance point at 2.5 GHz, and FIG. 8 shows a comparison of S-parameter results of simulation and measurement. As shown in FIG. 12, the radiation pattern and the electric field distribution at 2.5 GHz are shown in FIG. 11 and FIG. 12. As shown in FIG. 12, the electric field vectors are uniformly distributed perpendicularly to the patch. As a result, a magnetic field current in the form of a closed curve is generated and a monopole radiation pattern is formed as shown in FIG.

Also, it can be confirmed that there is a resonance point at a frequency lower than the 0th order resonance point, which is a -1st resonance point. The characteristics of the -1 st resonance can be confirmed through the antenna radiation pattern and the electric field distribution in Figs. 9 and 10. FIG. 9 shows an antenna pattern distribution having the same directivity as that of a general patch antenna, and FIG. 10 shows that the electric field vector appears as a half-wave resonance pattern.

FIG. 13 shows a comparison between the simulation results in the -1st and 0th order resonances and the actually measured radiation characteristics, and the results are similar. The 0th order resonant antenna is designed so that the 1st order resonance and the 0th order resonance characteristics are clearly seen. Although the antenna gain at the 0th order resonance point is as high as 5dBi and the radiation efficiency is more than 95%, a highly efficient antenna is designed, but the bandwidth is measured at about 80Mhz and the bandwidth is narrowed to about 3% .

Therefore, to improve the bandwidth, not only the 0th order but also the -1st portion appear distinctly, so the -1st order resonance frequency is shifted to the 0th order resonance frequency to expand the band. The first-order resonance point, which has a resonance point lower than the zeroth-order resonance point, must be increased in frequency in order to enlarge the bandwidth. Therefore, the series capacitance, which is a negative region, must be small. In order to lower the positive resonance frequency, The size should be large. That is, the C _L portion in FIG. 6 representing the equivalent circuit of the antenna must be small, and the L _R portion must be large.

Therefore, as shown in FIG. 14, while maintaining the overall antenna size, the center patch plane, which determines the series capacitance C _L , is reduced and the width of the ring mushroom, which determines the series inductance, L _R , is increased. This process leads to a decrease in C _L and an increase in L _R.

FIG. 15 is a result of the S parameter change as the ring mushroom area of FIG. 14 is increased. It can be seen that the bandwidth ratio can be extended from 3% to 30% adjacent to the first-order resonance frequency and the higher-order zero-order resonance frequency.

Fig. 16 shows the final designed antenna, and Fig. 11 shows S-parameter results comparing the simulation and measured values. In the simulation, it has a bandwidth of 770Mhz at the center frequency of 2.541GHz and about 30 % Of bandwidth. This is the bandwidth extended from 3% of the narrowband antenna to 10 times as much as the bandwidth of the narrowband antenna. Since the center frequency is 2.873GHz and the bandwidth is 1428MHz, the bandwidth is 57% It can be confirmed that the bandwidth is extended more than twice.

In Fig. 19, it is confirmed that the zeroth-order resonance occurs in the electric field distribution in the band. Accordingly, it can be seen from FIGS. 18 and 20 that the monopole radiation type is included in the entire band. As can be seen from FIG. 20, the results of the simulation and the simulation are similar to each other.

The present invention has a monopole type of linear antenna and low-profile characteristics, and has an antenna gain of about 3 dB and a high efficiency of more than 90% of a bandwidth of 30% or more, thereby replacing a linear antenna in a field requiring high gain and high efficiency. Lt; / RTI >

Claims (3)

delete In order to realize an antenna having an acyclic zero-order and a first-order resonance in which capacitive coupling occurs, the -1st resonance and the positive resonance are shifted to the 0th order resonance as the series capacitance value and the series inductance increase, respectively, Bandwidth,
A microstrip patch is coupled to the center of a ring mushroom structure having a shorting pin to generate a zero order resonance having a monopole radiation pattern,
And the 0th order resonance band is increased by decreasing the series capacitance when the area of the microstrip patch structure is reduced as the area of the ring mushroom structure is increased when maintaining the overall size of the antenna. The ring mushroom and the capacitive microstrip patch structure CRLH 0 Broadband and gain enhancement method of resonant antenna. 3. The method of claim 2,
Wherein the series capacitance is reduced when the ring circumference is reduced as the area of the ring mushroom structure is reduced and the series inductance is increased when the ring width is increased. The microstrip patch structure capacitively coupled with the ring mushroom. CRLH The broadband and gain How to improve.

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