CN103943960A - Novel multi-notch ultra-wideband antenna with stop-band units simultaneously loaded to feeder and patch - Google Patents

Abstract

The invention relates to the design of a trap wave ultra-wideband antenna, belonging to the technical field of electromagnetic wave propagation and reception. The present invention proposes a multi-notch ultra-wideband antenna with stop band units loaded on the feeder and radiation patch at the same time. Specifically, an open slot of 1/4 wavelength is used in the radiation patch, and different The size of the C-shaped half-wavelength open-circuit resonant unit realizes the three-stop notch ultra-wideband antenna, which can filter out interference from WiMAX (3.3-3.6GHz), WLAN (5.15GHz-5.35GHz, 5.725GHz-5.825GHz) systems . The antenna has the advantages of independently adjustable frequency points of each stop band and independently adjustable bandwidth of each stop band. Simulation results and actual measurement results prove that the antenna has good multi-frequency filtering characteristics.

Description

A new multi-notch ultra-wideband antenna with stop-band elements loaded on the feeder and the patch at the same time

technical field

The invention proposes a multi-band notch ultra-wideband antenna that filters out interference from WiMAX systems (3.3-3.6GHz) and WLAN systems (5.15GHz-5.35GHz, 5.725GHz-5.825GHz), and belongs to the technical field of electromagnetic wave propagation and reception .

Background technique

Since the FCC (Federal Communications Commission, Federal Communications Commission) issued 3.1GHz-10.6GHz to the commercial ultra-wideband communication frequency band, UWB technology (Ultra Wide Band, ultra-wideband) has become the most promising technology for indoor short-distance high-speed communication one. However, in the entire UWB frequency range, the existence of some narrowband systems will interfere with UWB communications, such as WiMAX systems and WLAN systems. As the core device of the UWB system, the UWB antenna has a great influence on the overall performance of the system. In order to filter out the interference of the narrowband system at the antenna end, it is of great significance to study the notched UWB antenna.

1. UWB technology

In 2002, FCC approved the 3.1GHz-10.6GHz frequency band as a commercial UWB application frequency band. UWB transmits extremely low-power signals on a wide frequency spectrum, and can achieve data transmission rates from hundreds of Mbit/s to several Gbit/s within a range of about 10 meters. Because of its strong anti-interference performance, high transmission rate, extremely wide bandwidth, low power consumption, low transmission power and many other advantages, it is mainly used in indoor communication, high-speed wireless LAN, home network, cordless phone, security detection, position determination, radar and other fields.

UWB technology is a carrier-free communication technology that uses nanosecond to microsecond non-sine wave narrow pulses to transmit data. Ultra-wideband communication technology originated in the 1940s, and the initial development form was relatively simple, only wireless pulse communication (document 1, Schantz H G.A brief history of UWB antennas[J].IEEE Aerospace and Electronic Systems Magazine,2004,19(4 ):22-26.). From the technical field, ultra-wideband communication technology is a communication technology that performs carrier-free modulation on those narrow pulses (the pulse width is between 0.20-1.5ns), also known as carrier-free (Carrier Free), time domain (Time Domain) or Impulse Radio (Impulse Radio) communication. Ultra-wideband communication technology has gigabit-level bandwidth and requires very little transmission energy, so it will bring us a brand-new data and voice communication method without occupying today's overcrowded frequency resources. In terms of performance, ultra-wideband technology is a communication system with a transmission rate of more than 100Mbps and an absolute bandwidth greater than 0.5GHz or a relative bandwidth ratio of 20% higher (document 2, Yarovoy A G, LigthartL P.Ultra-wideband technology today [C].Microwaves,Radar and Wireless Communications,2004.MIKON-2004.15th International Conference on.IEEE,2004,2:456-460.).

2. Planar monopole antenna

The printed monopole antenna is developed from the monopole antenna, and the printed circuit board (Printed Circuit Board, PCB) technology is used to realize the planarization of the monopole antenna. Planar printed monopole antennas are inexpensive, lightweight, easy to fabricate, and easy to integrate, which is a great advantage in increasingly integrated electronic devices. At present, the radiation body of the printed monopole antenna has various shapes, such as iron hook shape, straight strip shape, inverted F shape and so on.

Planar monopole antennas can be used in UWB systems due to their wide impedance bandwidth, easy fabrication, and good radiation characteristics. At present, the common ultra-wideband printed monopole antennas include round patches, square patches, and elliptical patches. Patches, pentagonal patches, hexagonal patches, gradient patches, etc.

The present invention adopts a circular patch monopole antenna (document 3, Liang J, Chiau C C, Chen X, et al. Study ofa printed circular disc monopole antenna for UWB systems [J]. Antennas and Propagation, IEEE Transactions on,2005,53(11):3500-3504.), the antenna has the advantages of simple structure, wide impedance bandwidth, stable radiation characteristics, good time domain characteristics, etc., and can cover the frequency range of 2.4GHz-10.3GHz.

3. UWB antenna notch technology

In the working frequency band of the UWB antenna, there are several narrowband wireless communication systems, such as global microwave access (WiMAX: 3.3GHz-3.6GHz), wireless local area network (WLAN) technology (such as 802.11a standard: 5.15-5.35GHz, 5.7125GHz-5.825GHz), in order to filter out potential interference from these systems, it is usually necessary to add a filter to the system, but this undoubtedly increases the cost and complexity of the system. A simpler and more effective method is to design a notch ultra-wideband antenna, and the filtering function can be realized at the antenna end. The so-called notch ultra-wideband means that it has filtering characteristics in a specific frequency band, and the energy in the notch frequency band cannot be effectively radiated and received, so that the filtering characteristics can be realized at the antenna end, eliminating the need to add additional filtering equipment to the system. Work.

According to the location where the notch is implemented, the current notch technology can be divided into: realize the stop band at the radiation patch; realize the stop band at the feeder; realize the stop band at the ground plane.

According to the notch realization method, the current filtering technology can be divided into: slotting (arc slot, U-shaped slot, rectangular slot, etc.) technology; adding parasitic patch technology; adding resonant strip technology; using fractal technology and genetic algorithm technology .

The main problem of the current single-band notch ultra-wide antenna is that the single-frequency stop band is too wide and cannot be adjusted, which wastes a lot of useful bandwidth. Therefore, there are a lot of literatures realizing multi-band notch UWB antennas. For example document 4 (document 4, Chu Q X, Yang YY.A compact ultrawideband antenna with3.4/5.5GHz dual band-notched characteristics[J].Antennas and Propagation,IEEE Transactions on,2008,56(12):3637- 3644.) By opening two C-shaped slots in the radiation patch, a dual-band notch ultra-wideband antenna with two frequency bands of 3.4-GHz and 5.5-GHz is realized. Since the two C-grooves are very close to each other and the coupling between them is strong, it is difficult to adjust the two stopbands independently. In Document 5 (Document 5, Zhang Y, Hong W, Yu C, et al. Planar ultrawideband antennas with multiple notched bands based onetched slots on the patch and/or split ring resonators on the feed line[J]. Antennas and Propagation, IEEE Transactions on, 2008, 56(9): 3063-3068.), through the introduction of multiple stop band units, a multi-band notch UWB antenna is realized, but some frequency bands are not the specified stop bands in the UWB band . Document 6 (Document 6, Ryu K S, Kishk A A. UWB antenna with single or dual band-notches for lower WLAN band and upper WLAN band[J]. Antennas and Propagation, IEEE Transactions on, 2009,57(12):3942 -3950.), two parasitic strips are used around the radiation patch to realize the stop bands of the 5.2GHz and 5.8-GHz frequency bands, so that the useful frequency bands between the stop bands can be used normally. Although the single-frequency stopband has an adjustable effect, due to the limitation of the space between the two parasitic strips, the coupling between the two is relatively serious. It is not easy to realize the independent adjustment of the dual-frequency stopband. Document 7 (Document 7, PengL, Ruan C L.UWB band-notched monopole antenna design using electromagnetic-bandgap structures[J].Microwave Theory and Techniques,IEEE Transactions on,2011,59(4):1074-1081.), EBG structures of different sizes are loaded on both sides of the antenna feeder to realize a dual-frequency independently adjustable notch ultra-wideband antenna. The principle is to place the stopband units on both sides of the antenna, and realize the independent adjustable bandwidth and frequency points of the double stopband through the relative independence of space. However, the literature did not consider the influence of the dielectric loss tangent during the simulation process, resulting in a relatively small standing wave ratio of the second stopband in the actual measurement of the antenna, and no obvious stopband effect. Document 8 (Document 8, Zhu F, Gao S, Ho T, et al. Multiple Band-Notched UWB Antenna with Band-Rejected Elements Integrated in the Feed Line[J].2013.), by using high dielectric constant and Low-loss medium, 1/4 wavelength metal strips and 1/4 wavelength open slots are loaded on the antenna feeder to realize a notch ultra-wideband antenna with multiple stop bands. The antenna has a strong filtering effect and is within the stop band The gain is reduced by 15dB and 10dB, respectively. But in triple-stopband UWB antennas, the range of the stopbands is too wide, leaving only a small fraction of usable bandwidth.

According to the above characteristics, the present invention proposes a new way to realize the stop band—combining the methods of realizing filtering technology in different positions, that is, loading the stop band unit on the antenna feeder and the radiation patch respectively, so as to realize multi-band notch ultra-wideband antenna. This method can realize the linear superposition of the two stop bands, and there is no obvious deviation from the original stop band. In addition, because each stopband unit has relative isolation in space, and is located at different ends of the antenna at the same time, and has a different notch mechanism, so the ultra-wideband antenna has the characteristic that each stopband is independently adjustable.

Contents of the invention

The multi-band notch ultra-broadband antenna designed by the present invention is composed of a monopole circular patch antenna fed by a microstrip line. Combining the feeder notch and the radiation patch notch, a multi-frequency independently adjustable notch ultra-wideband antenna is realized. Specifically, a rectangular open slot is first opened on the radiation patch, the length of the slot is 1/4 of the guided wave length, and the width of the slot mainly affects the bandwidth of the stop band. The invention realizes the stop band of 3.08-3.74 GHz by using the open slot, and is used for filtering the interference from the WiMAX system. Secondly, a C-shaped half-wavelength open-circuit resonant unit is loaded at the feeder. The total length of the resonant unit is half the wavelength of the center frequency of the stop band. The impedance bandwidth is mainly determined by the coupling spacing and the line width of the resonant unit. By loading a resonant unit at the feeder, a stop band of 4.88-6.18GHz is realized, and by loading resonant units of different sizes on both sides of the feeder, a dual stop band of 4.69-5.43GHz and 5.64-6.10GHz is realized for filtering Eliminate interference from WLAN systems.

Compared with the prior art, the present invention has the following advantages:

1. The notch technology adopted by the radiation patch is simple and easy to implement, the center frequency point and bandwidth of the stop band are easy to adjust, and the introduction of the notch technology will not affect the radiation characteristics in the working frequency band of the antenna.

2. The filter technology used in the feeder is simple and easy to implement, and the center frequency point and bandwidth of the stop band are easy to adjust. By loading half-wavelength resonant units of different sizes on both sides of the feeder line, dual-frequency filtering can be realized, and the two resonant units are located on both sides of the feeder line, separated in space, so the two notch frequency bands can be adjusted independently without interfering with each other.

3. The present invention combines the methods of feeder notch and radiation patch notch, so it is beneficial to realize notched ultra-wideband antenna with multiple stop bands. At the same time, since the stopband units are spaced apart from each other and the mutual coupling is small, it is easy to realize a trap ultra-wideband antenna with multiple stopbands and each stopband independently adjustable.

The working principle of the present invention is as follows:

First, the working principle of the planar monopole antenna is introduced. The present invention adopts a circular patch monopole antenna fed by a microstrip line, and the working frequency of the planar printed monopole antenna is mainly determined by a radiator. The circular radiation patch adopted in the present invention has good smoothness, so it can realize better impedance matching in a relatively wide frequency band, and can be used in an ultra-wideband system. In addition, the ground of the antenna is partially ground, only covering the bottom of the microstrip line, and there is no metal ground under the radiator.

Secondly, the working principle of filtering by slotting in the radiation patch is introduced. The present invention adopts an open slot, and the length of the slot is 1/4 wavelength corresponding to the central frequency of the stop band. After the opening slot is introduced, the current distribution in the patch will be changed, and the current path will be changed at the same time, which means that the energy of certain frequencies cannot effectively enter the radiation patch for radiation, forming a notch. When conducting theoretical analysis, the circuit model can be used to equivalent the slotted patch into an RLC parallel circuit connected in series with the antenna radiation resistance. At the resonant frequency of the RLC circuit, the impedance is very large, which will prevent the The energy in the frequency enters the radiation patch to realize the notch function.

The working principle of filtering in the feeder is introduced again. The present invention uses a half-wavelength open-circuit resonant unit loaded at the feeder. The total length of the resonant unit is 1/2 wavelength corresponding to the center frequency of the stop band. After the resonant unit is introduced, a strong coupling will be formed between the resonant unit and the feeder, resulting in a certain Energy in these frequencies is reflected back and cannot effectively enter the radiating patch, forming a notch. By introducing resonant units of different sizes on both sides of the feeder line, two stopbands can be realized. Since the resonant units are located on both sides of the feeder line and have spatial independence, the center frequency and bandwidth between the two stopbands can be independently adjusted.

Finally, the working principle of the multi-frequency controllable notch UWB antenna is introduced. Combining the feeder filter and the radiation patch to achieve filtering, the feeder and the radiation patch are loaded with corresponding frequency stop-band units at the same time to realize the multi-band notch ultra-wideband antenna, because the stop-band units are spatially isolated from each other , the mutual coupling is small, so the stop bands are independently adjustable, and a notch ultra-wideband antenna with multiple frequency bands and each stop band independently adjustable is realized.

Description of drawings

Figure 1(a) is a schematic diagram of the structure of a circular patch printed monopole antenna fed by a microstrip line. The medium used in the present invention is FR-4 copper clad laminate with a relative permittivity of 4.4, the size is W×L×h, the size of the antenna ground is W×L1, the width of the 50Ω feed microstrip line is Wf, and the radiation patch The radius of is r, and the distance between the feeding point and the antenna is d. The values of each parameter after optimization are: W=42mm, L=50mm, L1=20mm, h=1.5mm, Wf=2.7mm, r=10mm, d=0.3mm. Figure 1(b) is the simulation and measured VSWR diagram of the circular patch UWB antenna. The simulation shows that the frequency range of VSWR<2 is 2.44-10.27GHz, and the actual measurement shows that the frequency range of VSWR<2 is 2.67GHz-12GHz. It can be seen that the antenna completely covers the ultra-wideband frequency range 3.1GHz-10.6GHz promulgated by the FCC.

Figure 2(a) is a schematic diagram of the structure of a single-band notch ultra-wideband antenna with filtering implemented in the radiation patch. The present invention adopts a 1/4 wavelength open slot, and the size of the open slot is sl×sw. The simulation results show that the length sl of the slot mainly affects the center frequency point of the stop band, and the width sw of the slot mainly affects the bandwidth of the stop band. The optimized parameters are: sl=13mm, sw=0.4mm. Figure 2(b) shows the simulated and measured VSWR diagrams. The simulation shows that the frequency range of the stopband is 3.08-3.74GHz, and the center frequency is 3.45GHz; the actual measurement shows that the frequency range of the stopband is 3.11GHz-3.82GHz, and the center frequency is 3.52GHz. From the comparison chart, it can be seen that the simulation results are consistent with the measured results, the stop bands are in good agreement, and there is a slight difference at high frequencies.

Fig. 3(a) is a schematic diagram of the structure of a notch ultra-wideband antenna that realizes single-frequency filtering at the feeder. What the present invention adopts is the open-circuit resonant unit of 1/2 wavelength, and the size of the resonant unit is as shown in the figure, and the simulation result shows: the overall length (Lr+Lr1) of the resonant unit mainly affects the center frequency of the stop band, the distance between the feeder and the resonant unit The distance between them mainly affects the bandwidth of the stop band. After optimization, the parameters are: Lr=9mm, g=0.3mm, line width t=0.6mm, Lr1=4.2mm. Figure 3(b) shows its simulated and measured VSWR diagrams. The simulation shows that the frequency range of the stopband is 4.88-6.18GHz, and the center frequency is 5.54GHz; the actual measurement shows that the frequency range of the stopband is 5.45-6.32GHz, and the center frequency is 5.87GHz. It can be seen from the comparison chart that the measured results are shifted to high frequency, but there is still an obvious stop band.

Fig. 4(a) is a schematic structural diagram of a dual-band notch UWB antenna loaded with stop-band elements on both sides of the feeder. The present invention uses open-circuit resonant units of different sizes loaded on both sides of the feeder, and the sizes of each resonant unit are shown in the figure. The simulation results show that the right resonant unit mainly affects the first stopband, the left resonant unit mainly affects the second stopband, and the distance between the feeder and the resonant unit mainly affects the bandwidth of the stopband. The optimized parameters are Lr=9.5mm, Lr1=4mm, g=0.5mm, t=0.5mm, Ll=8mm, Ll1=4mm, and the distance cd=1.5mm between the center of the resonance unit and the center of the feeder. Figure 4(b) shows its simulated and measured VSWR diagrams. The simulation shows that the first stopband ranges from 4.69-5.43GHz, the center frequency is 5.25GHz, the second stopband ranges from 5.64-6.10GHz, and the center frequency is 5.85GHz; the actual measurement results show that the first stopband The range is 5.09-5.73GHz, and the center frequency is 5.55GHz; the second stopband ranges from 5.97-6.47GHz, and the center frequency is 6.18GHz. From the comparison chart, it can be seen that the measured results have shifted to the high frequency by about 300MHz, but the bandwidths of the two stop bands are basically unchanged.

Figure 5(a) is a schematic structural diagram of a dual-frequency notch UWB antenna in which the feeder and the patch simultaneously load the stop-band unit. That is, for the combination of the antenna 2 and the antenna 3 , the size of each stop band unit is consistent with the size of the antenna 2 and the antenna 3 . FIG. 5( b ) is a comparison chart of standing wave ratios of antenna 2 , antenna 3 , and antenna 5 . It can be seen that after the feeder notch is combined with the patch notch, the two stop bands of antenna 5 maintain good consistency with the stop bands of antenna 2 and antenna 3, and the bandwidth of the first stop band is 3.03-3.77GHz, basically There is no offset, and the bandwidth of the second stopband is 5.10-5.92GHz. Compared with antenna 3, the bandwidth is reduced, but the center frequency maintains a good consistency. This result can verify the correctness of the method proposed before. Combining the method of filtering by the feeder and the filtering by the radiation patch can well realize the superposition of their respective stop bands, which is conducive to simplifying the design of the multi-frequency notch ultra-wideband antenna . Figure 5(c) is a comparison diagram of the maximum gain of the simulated antenna 5 and antenna 1. It can be seen from the figure that after loading the stop band unit, the gain in the two notches is significantly reduced, and the maximum is at the frequency point of 3.5GHz The gain is reduced from 3.06dBi to -1.03dBi, a decrease of 4.09dB, and the maximum gain at the 5.55GHz frequency point is reduced from 3.36dBi to -4.81dBi, a decrease of 8.17dB, which verifies the effectiveness of the dual-frequency notch, which can It is used in UWB system to filter out the interference of WiMAX and WLAN system. Figure 5(d) shows the simulated and measured VSWR diagrams. The measured results show that the bandwidth of the first stopband is 3.02-3.82GHz, which is consistent with the simulation results; the bandwidth of the second stopband is 5.40-6.22GHz, which is consistent with Compared with the simulation results, the high frequency is shifted by about 300MHz. It is speculated that it is likely to be caused by SMA connectors and manufacturing errors.

FIG. 6( a ) is a schematic structural diagram of a three-band notch ultra-wideband antenna combined with antenna 2 and antenna 4 . The size of each stop band unit is consistent with the size of antenna 2 and antenna 4 . FIG. 6( b ) is a comparison chart of standing wave ratios of antenna 2 , antenna 4 , and antenna 6 . It can be seen that after the feeder notch is combined with the patch notch, antenna 6 realizes three stop bands, and each stop band maintains a good consistency with the stop bands of antenna 2 and antenna 4 respectively. The bandwidth of the first stopband is 3.03-3.74GHz, and there is basically no offset. The bandwidth of the second stopband is 4.85-5.40GHz, and the bandwidth of the third stopband is 5.64-6.00GHz. Compared with antenna 4, The bandwidth varies, but the center frequency remains very consistent. This result can verify the correctness of the method proposed before. Combining the method of filtering by the feeder and the filtering by the radiation patch can well realize the superposition of the respective stop bands, which is beneficial to the design and adjustment of the multi-frequency notch ultra-wideband antenna . FIG. 6( c ) is a comparison diagram of the simulated maximum gain of antenna 6 and antenna 1 . It can be seen from the figure that after the stopband unit is loaded, the gain in the three notches decreases significantly, from 3.06dBi to -1.16dBi at 3.5GHz, a decrease of 4.22dB; at 5.25GHz from 2.56dBi to -5.57dBi, a decrease of 8.13dB; at 5.8GHz from 3.72dBi to -2.44dBi, a decrease of 6.16dB, which verifies the effectiveness of the triple-frequency notch and can be used in UWB systems to filter out WiMAX and WLAN systems interference. Figure 6(d) shows the comparison between the simulation and actual measurement standing wave ratio. The actual measurement results show that the bandwidth of the first stopband is 3.01GHz-3.80GHz, which is consistent with the simulation results; the bandwidth of the second stopband is 5.22-5.73GHz , the bandwidth of the third stopband is 5.94-6.44GHz, compared with the simulation results, it shifts to high frequency by about 300MHz. It is speculated that it is likely to be caused by SMA connectors and manufacturing errors.

Detailed ways

The specific embodiments of the present invention are as follows.

First, select an ultra-wideband antenna that covers the commercial frequency band promulgated by the FCC. According to the UWB system's requirements for ultra-wideband antenna, small size, and low cost, combined with the characteristics of low cost, light weight, and easy fabrication of monopole antennas, the circular patch ultra-wideband antenna in Document 3 was selected as a prototype. The specific antenna The structure is shown in 1(a).

Second, notches are implemented at the feeder and radiating patches, respectively. Specifically, a 1/4 wavelength open slot is opened in the radiation patch, and the size of the open slot is sl×sw. The simulation results show that the length sl of the slot mainly affects the center frequency point of the stop band, and the width sw of the slot Mainly affects the bandwidth of the stopband. The optimized parameters are sl=13mm, sw=0.4mm, and the frequency range of the stop band is 3.08-3.74GHz, which can be used to filter out the interference of the WiMAX system. The specific structure is shown in Figure 2(a). Loading a 1/2 wavelength resonant unit on one side of the feeder can also achieve single-frequency notch. The simulation results show that: the overall length of the resonant unit (Lr+Lr1) mainly affects the center frequency of the stop band, and the distance between the feeder and the resonant unit The spacing mainly affects the bandwidth of the stopband. The parameters after optimization are: Lr=9mm, g=0.3mm, line width t=0.6mm, Lr1=4.2mm, and the frequency range of the stop band is 4.88-6.18GHz, which can be used to filter out the interference of the WLAN system. Loading different sizes of 1/2 wavelength open-circuit resonant units on both sides of the feeder can realize dual-frequency notch. The simulation results show that the right resonant unit mainly affects the first stop band, and the left resonant unit mainly affects the second stop band. The distance between the feed line and the resonant unit mainly affects the bandwidth of the stop band. The optimized parameters are Lr＝9.5mm, Lr1＝4mm, g＝0.5mm, t＝0.5mm, Ll＝8mm, Ll1＝4mm, the distance between the center of the resonant unit and the center of the feeder cd＝1.5mm, the first stop band The range of the stop band is 4.69-5.43GHz, and the range of the second stop band is 5.64-6.10GHz, which can be used to filter out the interference of the WLAN system. All antennas have been tested and verified to ensure the correctness of the simulation results.

Thirdly, the method of filtering by the feeder and the filter by the radiation patch are combined, and the stopband unit of the corresponding frequency is loaded on the feeder and the radiation patch at the same time. Specifically, combining antenna 2 and antenna 3, a dual-band notch ultra-wideband antenna is realized, and the two stop bands of the antenna are in good agreement with those of antenna 2 and antenna 3. The bandwidth of one stopband is 3.03-3.77GHz, and there is basically no offset. The bandwidth of the second stopband is 5.10-5.92GHz. Compared with antenna 3, the bandwidth has been reduced, but the center frequency point has remained very good. consistency. Similarly, antenna 2 and antenna 4 are combined to realize a three-band notch ultra-wideband antenna, and the stop bands of the antenna are in good consistency with the stop bands of antenna 2 and antenna 4 respectively. The bandwidth of the first stopband is 3.03-3.74GHz, and there is basically no offset. The bandwidth of the second stopband is 4.85-5.40GHz, and the bandwidth of the third stopband is 5.64-6.00GHz. Compared with antenna 4, The bandwidth varies, but the center frequency remains very consistent. This result can verify the correctness of the method proposed before. Combining the method of filtering by the feeder and the filtering by the radiation patch can well realize the superposition of the respective stop bands, which is beneficial to the design and adjustment of the multi-frequency notch ultra-wideband antenna . In addition, the gain variation of the stop band is analyzed to verify the effectiveness of the notch. Finally, all the antennas are fabricated and measured to verify the correctness of the simulation results.

Claims (3)

1. propose a kind of effective many trap UWB antennas implementation method, realize stopband and feeder line by radiation patch and realize the method for stopband and combine, load stopband unit corresponding to different trap frequencies at feeder line and radiation patch simultaneously.The method can realize the stack of both stopbands, and the not significantly skew of relatively former stopband; The multiband trap UWB antenna that utilizes the method to realize has advantages of that stopband frequency is easily adjusted, bandwidth of rejection is easily adjusted, independent adjustable between each stopband.

2. according to method described in claim 1, realized the trap UWB antenna of a double frequency-band.Concrete methods of realizing is the rectangular aperture groove of having opened 1/4 wavelength in radiation patch, loaded C shape half-wavelength open circuit resonant element simultaneously on feeder line right side, realized the trap UWB antenna of dual-attenuation (3.03-3.77GHz, 5.10-5.92GHz), can filtering from the interference of WiMAX system and wlan system.

3. according to method described in claim 1, realized the trap UWB antenna of three frequency bands.Concrete methods of realizing is the rectangular aperture groove of having opened 1/4 wavelength in radiation patch, loaded respectively the C shape half-wavelength open circuit resonant element of different size simultaneously in feeder line both sides, realized the trap UWB antenna of three stopbands (3.03-3.74GHz, 4.85GHz-5.40GHz, 5.64GHz-6.00GHz), can filtering from the interference of WiMAX system and wlan system.