CN105762478A - Four-mode resonator loaded with high-impedance lines - Google Patents

Abstract

The invention discloses a four-mode resonator loaded with high-impedance lines, and relates to the field of microwave passive devices. The resonator is composed of a dual-mode resonator and two symmetrically-distributed high-impedance lines connected with a transmission line, wherein the dual-mode resonator is a folding half-wave resonator, the two arms of a metal patch of the resonator are folded inward, the bottom center of the patch is provided with a via hole, and the two high-impedance lines are attached to the two sides of the dual-mode resonator symmetrically and connected with the transmission line. All the structures are printed on the front of a dielectric substrate, and the back of the substrate is completely covered by metal. The resonator overcomes the following defects: the existing ultra-wideband notch device needs multiple resonators to realize multiple notch stop bands, performances such as frequency selectivity and notch bandwidth need improvement, and the resonance structure can hardly apply to or be transplanted to different UWB systems of other radiation units.

Description

A Four-mode Resonator Loaded with High Resistance Line

technical field

The invention relates to the field of microwave passive devices, in particular to a double-mode resonator based on half-wavelength.

Background technique

Ultra-wideband (UWB) wireless communication systems have attracted widespread attention. UWB antennas and filters, as the key components of UWB wireless communication systems, play a vital role in UWB wireless communication systems. However, there are still some problems in the practical application of UWB antennas. One of them is that some existing wireless communication systems have occupied some frequency bands in the UWB range, such as WiMAX (3.3-3.8GHz), IEEE802.11a (5.15- 5.35GHz&5.725～5.825GHz) or X-band satellite communication service (7.25～8.395GHz), etc. Therefore, in order to eliminate the influence of these wireless systems on itself, the UWB system needs UWB microwave passive devices with notch characteristics. Such as antennas, filters, etc.

There are currently some solutions to the above problems. For example, slot structures are etched on the radiator of the antenna [see J.Kim, C.S.Cho, and J.W.Lee, "5.2GHznotchedultra-widebandantennausingslot-typeSRR," Electronics.Letters, vol.42, no.6, pp.315 -316, Mar.2006.], etch the slot structure on the feeder [see Y.H.Zhao, J.P.Xu, and K.Yin, "Dualband-notched ultra-wideband microstripantenna using asymmetrical spurlines," Electronics.Letters, vol.44, no.18, pp. 1051-U8, Aug.2008] or add a tuned metal stub structure to the antenna structure [see C.Pan, J.Duan, W.Tu, and J.Jan, "Band-notched ultra-wideband planarmonopole antenna using shunt open-circuitedstub," Microwave and Optical Technology Letters , vol.53, no.7, pp.1535-1537, Jul.2011.] can realize the band-stop characteristics of the antenna, but in these structures, multiple resonant structures need to be used to generate multiple notches, This will undoubtedly increase the complexity of the wireless system. Although multi-mode resonators have been used in antennas with multi-notch characteristics [see Y.Sung, "Tripleband-notched UWB planarmonopole antenna using a modified H-shaped resonator," IEEE Transactions on Antennas and Propagation, vol.61, no.2, pp.953-957, Feb. 2013; H. Liu and Z. Xu, “Design of UWB monopole antenna with dual notched bands using one modified electromagnetic-bandgap structure,” The Scientific World Journal, vol. 2013, pp. 917965, 2013; K. D. Xu, Y. Zhang, R. J. Spiegel, Y. Fan, Q. Designofastub-loadedring-resonatorslotforantennaapplications,"IEEETransactionsonAntennasandPropagation,vol.63,no.2,pp.517-524,Feb.2015.], but these notch antennas using multimode resonators, their frequency selectivity and notch bandwidth, etc. Performance still has a lot of room for improvement. More importantly, since these resonant structures are all changes to the structure of the antenna radiating unit, it is difficult to apply or transplant to other different radiating structures in other UWB systems.

Contents of the invention

The purpose of the present invention is to propose a four-mode resonator that can produce notches, which overcomes the need for multiple resonators, frequency selectivity and notch bandwidth in existing ultra-wideband notch devices to achieve multiple notch stop bands The performance needs to be improved and the resonant structure is difficult to apply or be transplanted to other UWB systems with different radiating units.

The technical solution adopted by the present invention to solve the technical problem is: a four-mode resonator loaded with high-impedance lines, the resonator is composed of a dual-mode resonator and two symmetrically distributed high-impedance lines connected to transmission lines, wherein , the dual-mode resonator is a folded half-wavelength resonator, the two arms of the metal patch are folded inward, there is a via hole at the center of the bottom of the patch, and two high-impedance lines are symmetrically attached to the double mode resonator on both sides and connected to the transmission line. All the above structures are printed on the front side of the dielectric substrate, and the backside of the substrate is completely covered with metal. Therefore, the present invention is a four-mode resonator loaded with high-impedance lines. The resonator includes: a metal floor, a dielectric substrate arranged on the metal floor, and a resonance unit arranged on the dielectric substrate; the resonance unit includes: a dual-mode resonance device, high-impedance connecting line, transmission line, wherein the dual-mode resonator is an unclosed symmetrical square ring structure, and the two ends of the ring structure have branches extending inward; the bottom of the dual-mode resonator is facing the center of the opening A through hole is provided; a transmission line is provided facing away from the opening of the dual-mode resonator, and the two sides of the dual-mode resonator are respectively connected to the transmission line through two high-impedance connecting lines.

Further, one end of the two high-impedance connecting lines is respectively connected to two corners of the opening where the dual-mode resonator is located, and the other end is connected to the transmission line.

Further, the two high-impedance connecting lines are in the shape of a square wave, and the direction is perpendicular to the transmission line.

The present invention has following beneficial effect:

(1) The present invention generates two notches within the UWB frequency band. Compared with the method of using multiple resonators to realize multiple notch stop bands, its structure is very simple.

(2) Based on the proposed resonator, each notch will contain two transmission zeros, which can improve the bandwidth of the notch compared with the previous single-zero notch design.

(3) Based on the proposed resonator, a transmission pole will be generated on both sides of each notch. By adjusting the physical size of the resonator, the position of the transmission pole will be very close to the transmission zero in the notch, thus improving the Frequency selectivity of the notch.

(4) Compared with the resonator using the same resonator structure without adding two high-impedance lines, the present invention has a higher suppression level in the stop band, and at the same time reduces the difficulty of processing the gap between lines.

(5) When the resonator of the present invention is used for an antenna, it can produce a notch effect when it is placed near the feeder line, and can be well transplanted into various UWB antennas with different radiating units.

Description of drawings

Figure 1 is a traditional dual-mode resonator

Fig. 2 is the novel resonator proposed by the present invention

Fig. 3 is a deformed version of the present invention (the situation after the high-resistance line is folded)

Figure 4 is the S1 ₁ simulation results of Figure 1 and Figure 2 in the case of weak coupling without vias in Figure 1. The dimensions of the resonator are: l ₁ =15.24, l ₂ =14.6, w ₁ =0.7, w ₂ =0.1, w ₃ =1.1, S ₁ =0.2, S ₂ =0.16, and the radius of the through hole is r=0.2

Fig. 5 shows the reflection coefficient change (S ₁₁ ) of the resonator in the present invention under different size parameters (a) l ₁ , (b) l ₂ , (c) w ₂

Fig. 6 is the structural diagram of (a) UWB reference antenna and (b) notch UWB antenna in the embodiment

Fig. 7 is the simulation result of the return loss (S ₁₁ ) of the UWB reference antenna and the notch UWB antenna in the embodiment

Fig. 8 is (a) reference UWB filter front (b) reference UWB filter back (c) UWB notch filter based on the resonator of the present invention in the embodiment

Figure 9 is the S-parameter simulation result of Figure 8(c)

detailed description

The present invention will be further described below with reference to the accompanying drawings and embodiments: A new type of four-mode resonator is shown in FIG. 2 . The lower surface of the dielectric substrate is completely covered by metal, and the upper surface metal layer includes a U-shaped resonator with arms folded inward (see Figure 1(a)), and a metallized via hole in the center of the bottom. On both sides of the resonator, two high-impedance microstrip lines extend from the two arms of the resonator to the vicinity of the feeder, connecting the resonator with the feeder. The feeder is a 50Ω microstrip line. Further, to reduce the size of the resonator, the high-impedance microstrip line can be designed in a meandering shape while keeping its length constant, as shown in Figure 3.

Principle of the present invention is:

Adding a via in the center of the original U-like single-mode resonator (see Figure 1(b)) can generate an additional resonant mode near the frequency of the original resonant mode. Since the frequencies of these two modes are close to each other, they can be combined into a wider stopband. On this basis, adding two high-impedance lines on both sides of the resonator can reduce the center frequency of the resonator stopband and generate an additional stopband at a higher frequency. These two stopbands are compared to the additional The stop band before the high impedance line has more superior frequency selection characteristics and higher frequency band suppression level, and there are more zero points to improve impedance matching. (See Figure 4)

After test data analysis, adjusting the size of the present invention can adjust the center frequencies of the two stop bands. As shown in Figure 5(a), when the size of l ₁ is increased, the center frequencies of both stop bands of the resonator can be decreased, and increasing the size of l ₂ can reduce the center frequency of the higher frequency stop band, However, the lower frequency stop band changes slightly. When w ₂ is increased, the center frequency of the lower frequency stop band will decrease, while the center frequency of the high frequency stop band will not change.

Based on these characteristics of the present invention, it is only necessary to design the size of l ₁ first, adjust the frequency of the low-frequency stop band to the required frequency, and then adjust l ₂ to adjust the frequency of the high-frequency stop band to the required frequency , in the process, there will be a slight shift in the frequency of the low-frequency stopband, so it is necessary to adjust w ₂ to compensate for the shift in the frequency of the low-frequency stopband.

Embodiment 1: UWB notch antenna

In order to further illustrate the practicability of the above solution, a specific example is given below, which is a high-selectivity double-notch ultra-wideband planar monopole antenna. The dielectric substrate uses RT/Duorid4350 substrate with a thickness of 34mm×25mm×0.508mm and a dielectric constant of 3.48. The structural diagram of the antenna is shown in Figure 6(b), and the antenna is designed based on Figure 6(a). The simulation results are shown in Figure 7. It can be seen that the antenna produces two notch stop bands at 4.77-5.35GHz and 7.26-8.35GHz. Except for the two notch stop bands, the return loss S ₁₁ is at 3.2-12GHz The internal reflection coefficient is still less than -10dB, and the reflection coefficient in the 10.5-13GHz passband has been significantly improved.

Embodiment 2: UWB notch filter

Based on the traditional UWB filter (see Figure 8(a) and (b)), the new UWB filter (see Figure 8(c)) loaded with the resonator of the present invention. The circuit shown in Figure 8(c) produces a UWB response with two notches. Each notch has two transmission zeros, as shown in Figure 9.

Those of ordinary skill in the art will appreciate that the embodiments described herein are to help the reader understand the principles of the present invention and it should be understood that the scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations without departing from the present invention based on the technical revelations disclosed in the present invention, and these modifications and combinations are still within the protection scope of the present invention.

Claims (3)

1. A four-mode resonator loaded with a high-impedance line, the resonator comprising: a metal floor, a dielectric substrate arranged on the metal floor, a resonant unit arranged on the dielectric substrate; the resonant unit comprises: a dual-mode resonator , high-impedance connecting line, transmission line, wherein the dual-mode resonator is an unclosed symmetrical square ring structure, and the two ends of the ring structure have branches extending inward; the bottom of the dual-mode resonator is set at the center of the opening A through hole; facing away from the opening of the dual-mode resonator, a transmission line is arranged, and the two sides of the dual-mode resonator are respectively connected to the transmission line through two high-impedance connecting lines. 2. A kind of four-mode resonator loaded with high-impedance lines as claimed in claim 1, wherein one end of the two high-impedance connecting lines is respectively connected to two corners of the opening edge where the dual-mode resonator is located, and the other One end is connected to the transmission line. 3. A four-mode resonator loaded with high-impedance lines as claimed in claim 1, characterized in that the two high-impedance connecting lines are in the shape of square waves, and the direction is perpendicular to the transmission line.