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1.
A broadband high‐gain circularly polarized (CP) microstrip antenna operating in X band is proposed. The circular polarization property is achieved by rotating four narrow band linearly polarized (LP) microstrip patch elements in sequence. Since the conventional series‐parallel feed network is not conducive to the miniaturization of the array, a corresponding simplified feed network is designed to realize the four‐way equal power division and sequential 90° phase shift. With this feed network, the impedance bandwidth (IBW) of the CP array is greatly improved compared with that of the LP element, while maintaining a miniaturized size. Then, parasitic patches are introduced to enhance the axial ratio bandwidth (ARBW). A prototype of this antenna is fabricated and tested. The size of proposed antenna is 0.93λ0 × 0.93λ0 × 0.017λ0 (λ0 denotes the space wavelength corresponding to the center frequency 10.4 GHz). The measured 10‐dB IBW and 3‐dB ARBW are 13.6% (9.8‐11.23 GHz), 11.2% (9.9‐11.07 GHz) respectively, and peak gain in the overlapping band is 9.8 dBi. 相似文献
2.
A coaxial cavity antenna excited by a stacked circular microstrip antenna is investigated as a feed for prime‐focus parabolic reflector antennas. The radiation pattern of the proposed cavity‐backed antenna is saddle shaped, which widens the ?10 dB beamwidths and increases the reflector efficiency especially for deep reflectors with small focal length‐to‐diameter ratios. With a single‐probe feed, the co‐polar radiation pattern is slightly asymmetric in the E‐plane, but is made symmetric by a differential feeding technique, using two probes. The impedance bandwidth of the proposed feed antenna is 20%. The antenna was fabricated and tested, and it exhibited good agreement between simulation and measurement results. The gain factor of the feed was also studied with a circular‐symmetric reflector and provided a gain factor of 79% at f/D = 0.375. This type of feed can be used as an alternative to conventional horn or waveguide feeds, where reduced size and light‐weight are desirable with added advantage of easy integration with electronics. 相似文献
3.
A compact sequential‐rotation array with serial feed and three probes using multi‐layer substrate is proposed. The most compact shape for the microstrip patches are selected with the optimization for the axial ratio and return loss bandwidth. The gain, return loss, and axial ratio bandwidths of the antenna are improved significantly by converting three patches to one circular. The patch radius and the position of probes are selected to form circular Poynting vectors around it where the maximum power is present at large frequency range. While the two layers of the structure use similar board this structure only uses a substrate and three simple pins. Also the total area of the antenna is limited to the microstrip patch and it has a straightforward fabrication steps. So the wideband antenna is relatively inexpensive and compact. The antenna has 21.4% 3 dB axial ratio bandwidth in simulation and 21.1% in fabrication. Consequently, the serial‐multi‐fed circular patch with unique angular and phase arrangements is suitable for many applications as the antenna arrays. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:529–535, 2014. 相似文献
4.
微带阵列天线的使用对飞机的隐身性能、机动性能等都具有非常重要的现实意义,在分析矩形微带天线设计原理的基础上,依据指标设计要求,完成了一个C频段微带天线阵的设计;同时,利用三维电磁场仿真软件(Ansoft HFSS)进行了仿真,并对其设计的参数进行了优化;在此基础上,通过实物加工,暗室实测,以及与AnsoftHFSS仿真结果进行比较,达到了C频段微带天线阵设计的目的,具有一定的实用工程价值. 相似文献
5.
This article presents a high‐isolation dual‐frequency rectangular patch antenna utilizing microstrip feed line integrated with a cascade defected microstrip structure (CDMS). Two types of CDMS are added, T‐shaped CDMS and Dumbbell‐T‐shaped CDMS. Simulation results show using these structures improve isolation up to 70 dB and reduce harmonic signals from transmitter. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011. 相似文献
6.
A coaxial line to a rectangular waveguide junction, backed by an iris-coupled cavity, is analyzed using a new approach based on the five-cavity moment method. The scattering matrix of the junction is obtained by combining the mode-matching method and an interpolation technique. The computed results are checked for orthogonality and unitary conditions, and are verified against experimental results. The proposed structure and the analysis method will be useful in the design of extracted pole filters, diplexers, and multiplexers. © 1998 John Wiley & Sons, Inc. Int J RF and Microwave CAE 8: 20–26, 1998. 相似文献
7.
A novel single‐fed circularly polarized wideband, compact and lightweight microstrip patch antenna (MPA) is proposed. The antenna is designed in a simple two‐phase procedure to achieve wideband and circular polarization. In the first phase, an off‐centered L‐shaped feeding arrangement is employed to obtain wideband (|S11| < ?10 dB) over 10.6 GHz to 14.7 GHz with an improved peak gain of 5.25 dBi. In the second phase, the radiating patch is symmetrically truncated and two modified‐parasitic patches are added to ensure <3 dB axial ratio over 11.4 GHz to 12.8 GHz. A prototype has been fabricated and the measured results show close agreement with the simulation. The proposed antenna is suitable for fixed satellite and broadcast satellite communication in Ku‐band range. 相似文献
8.
9.
Morteza Kazerooni Navid PourRamzan Gandji Ahmad Cheldavi Mahmoud Kamarei 《国际射频与微波计算机辅助工程杂志》2010,20(6):603-610
In this article a cascaded defected microstrip structures (CDMS) is proposed as the feed line of an inset patch microstrip antenna. Using this feed line, the effective radiation is improved; the higher order harmonics are completely suppressed, the size of antenna is about 10% reduced and also the front‐to‐back ratio parameter is greatly improved. In comparison to a conventional microstrip patch antenna without the CDMS, the radiated power of the CDMS patch antenna at harmonic frequencies even up to the 4th harmonic has been drastically decreased. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. 相似文献
10.
该文提出了一种新颖超宽带微带天线。该天线由微带宽槽天线的基本结构变形而来,其结构由矩形馈电微带贴片与矩形宽槽孔贴片组成。矩形宽槽孔开在金属GND板上,而矩形馈电贴片在介质板的另一面并在矩形宽槽孔框内偏下方。贴片与馈电线对接处采用渐变结构来达到阻抗匹配。以矩形宽槽尺寸为主构成了低频段的等效谐振电长度,而馈电贴片尺寸构成了高频段的等效谐振电长度。在各自的谐振频区上,矩形宽槽与馈电微带贴片两者相互耦合,构成两谐振电长度的天线叠合组成为一共面天线,从而拓展了天线的带宽。该文运用HFSS仿真软件,根据设定尺寸进行了仿真设计,制备了两只不同频段的样品天线。仿真结果和实验结果基本一致,表明该原理设计出的天线可实现超宽带特性。 相似文献
11.
在高速列车长期、快速行驶中,其转向架金属结构会因疲劳、应力、环境等因素影响,产生金属裂纹。为了在高速列车中的转型架金属表面实现远距离无损检测并判断是否存在裂纹,设计了一种应用在超高频频段的微带贴片型射频识别（Radio Frequency Identification,RFID)抗金属标签,配合RFID芯片,标定RFID阅读器与标签天线的位置和其发射天线的功率,当金属表面存在裂纹时标签天线谐振频率会向低频移动,并产生影响导致RFID系统识别距离的改变,从而实现金属表面裂纹检测。使用高频结构仿真(High Frequency Structure Simulator,HFSS)软件对天线结构进行优化,使其与芯片阻抗匹配,模拟了天线在金属表面存在裂纹的情况。由仿真结果可以分析得出：设计的无线有芯片微带贴片型RFID转向架表面裂纹检测标签能够有效地实现远距离监测金属表面裂纹长度、方向的变化情况。 相似文献
12.
Sumita Shekhawat Pratibha Sekra V. K. Saxena J. S. Saini D. Bhatnagar 《国际射频与微波计算机辅助工程杂志》2011,21(4):407-412
A novel dual‐frequency broadband design of a single‐layer single‐feed circular microstrip antenna with an off‐centered Y‐slot is demonstrated in this communication. By selecting a suitable location of the Y‐slot in the circle, the proposed antenna on glass epoxy FR‐4 substrate not only resonates efficiently at two closely spaced frequencies (2.736 and 2.868 GHz) but also offers improved bandwidth (210 MHz or 7.5%) in comparison with a conventional circular microstrip patch antenna (～2%). From the measured results, almost identical broadside radiation patterns are obtained at two resonant frequencies, and the variation of less than 1 dBi in gain values is achieved in the frequency range where broadband behavior is observed. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011. 相似文献
13.
Artificial neural networks modeling have recently acquired enormous importance in microwave community especially in analyzing and synthesizing of microstrip antennas (MSAs) due to their generalization and adaptability features. A trained neural model estimates response very fast, which is nearly equal to its measured and/or simulated counterpart. Thus, it completely bypasses the repetitive use of conventional models as these models need rediscretization for every minor changes in the geometry, which itself is a time‐consuming exercise. The purpose of this article is to review this emerging area comprehensively for both analyzing and synthesizing of the MSAs. During reviewing process, some untouched cases are also observed, which are essentially required to be resolved for antenna designers. Unique and efficient neural networks‐based solutions are suggested for these cases. The proposed neural approaches are validated by fabricating and characterizing of the prototypes too. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:747–757, 2015. 相似文献
14.
李锦屏 《自动化与仪器仪表》2014,(8):10-11
借助MATLAB强大的计算与图像处理功能,绘制了分别调整半微带长及电介质高的屏蔽微带线电场结构图,屏蔽微带线微带周围及介质交界面的电场结构图,实现了屏蔽微带线场图的可视化,对工程应用及教学有一定的帮助. 相似文献
15.
This article presents a new analytical method to predict crosstalk of a homogeneous terminated two microstrip coupled lines over a ground plane using transmission line theory. The derived formula is frequency and location dependent, which can be used to quickly estimate the crosstalk of a coupled line. Also, the effect of the geometrical parameters of the lines and load are included in the derived formula. Presented method can be used for the other types of coupled lines including lossy or lossless lines. To verify the accuracy of the introduced method, a few microstrip coupled line structures with different geometrical parameters are considered numerically and experimentally. The results of crosstalk based on the proposed analytical methods, simulation study using high frequency structure simulator and those obtained by measurements are reported and compared with each other. It is shown that our proposed method accurately estimates the amount of crosstalk for a two microstrip coupled lines. 相似文献
16.
Edge feeding of a circular patch antenna by a microstrip line has been achieved by utilizing the circumferential variation of the field which is fixed by loading the patch. However, loading splits the degenerate modes and gives rise to cross‐polarization. Three different techniques are presented to analyze the loaded circular patch antenna. Comparison with the measured results for input impedance and radiation patterns shows good agreement. The concept used here is very general and can be applied to the edge feeding of any ring antenna. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 74–85, 2001. 相似文献
17.
Neng‐Wu Liu Mei‐Jiao Sun Lei Zhu Zhi‐Hui Jia Lu‐Yang Ji Guang Fu Hui‐Li Zheng 《国际射频与微波计算机辅助工程杂志》2020,30(3)
A compact monopolar microstrip patch antenna (MPA) with enhanced‐bandwidth is proposed. In order to achieve the miniaturized patch, the zeroth‐order mode of the MPA instead of its higher‐order modes is employed at first by loading the shorting pin around the center of the patch. After that, a L‐shaped microstrip line with a shorting pin is introduced at the periphery of the patch radiator to excite an additional non‐radiative mode for bandwidth enhancement. In final, the proposed MPA is fabricated and measured. The results illustrate that the antenna generates an enhanced‐bandwidth of about 4.1% ranging from 2.39 to 2.49 GHz, which is significantly larger than that of the traditional MPA around 1%. Meanwhile, the dimensions of the radiating patch are obviously decreased down due to the employment of zeroth‐order mode, which are kept as small as about 0.17 λ0 × 0.22 λ0 × 0.026 λ0 (λ0 is the free‐space wavelength). 相似文献
18.
In this article, a metamaterial inspired microwave absorber is used to reduce the cross‐polarization (XP) level of the radiated wave in microstrip antenna (MSA). A microwave absorber unit‐cell has been analyzed and implemented to reduce the cross polarization (XP) level in a single element and a 2 × 2 microstrip patch array antennas. The antennas have been designed on a FR‐4 substrate of thickness 0.8 mm at 10.1 GHz center frequency. The 2 × 2 patch array antenna with and without the absorbers have been experimentally verified for the S11 parameter, the radiation pattern, and the XP suppression in H‐plane and a good comparison has been found. 相似文献
19.
A novel high‐performance high Q filter with ultra‐wide spurious‐free stopband and thermally stable performance is introduced using higher order mode of the coaxial resonator. The 7‐pole Chebyshev and a 5‐pole cross‐coupled filter are designed at Ka‐band to validate the concept. A compact cross‐coupled waveguide filter is introduced with a different approach to realize cross‐coupling makes the filter compact. The coaxial resonator and waveguide resonator filter have the same configuration, and their performances are compared at ambient and over the temperature. The high power analysis is done for both these filters to find their power handling capability. The high power performance of the coaxial resonator filter is superior, and it can handle 45.525 kW peak power. This filter is suitable to be used as pre‐select filter in millimeter wave payloads as well as for high power filtering applications. 相似文献
20.
Half‐hexagonal microstrip antenna (H‐HMSA) is a compact version of HMSA, as it resonates at the same fundamental mode frequency. In this article, a compact configuration of a single layer, broadband gap‐coupled H‐HMSA has been proposed. Gap‐coupled H‐HMSA is fed indirectly by a λ/2 microstrip‐line resonator. Broad bandwidth (BW) is achieved with an effective use of resonance introduced by λ/2 resonator and gap‐coupled half‐hexagonal radiating patches. A peak gain of 7.07 dBi and measured BW (S11 ≤ ?10 dB) of 11.5% at the center frequency of 5.2 GHz have been achieved, which occupies a small volume of 0.023 λ03 including the ground plane. The radiation patterns remain in the broadside direction throughout the return loss BW. Simulated results of the proposed antenna configuration are experimentally validated with good agreement. 相似文献