Compact and simple bandpass filter (BPF) structure using microstrip isosceles triangular patch resonator (ITPR) is proposed. The new filter design technique is based on two main ideas: Firstly, cutting the corners of the triangular structure, to make the filter size more compact. Secondly, etching slit in staircase form near the base of the triangle in order to improve the filter performances. The proposed filter was designed and fabricated on Taconic CER-10 substrate with a relative dielectric constant of 10 and a thickness of 0.64 mm using standard photolithography process. The final dimension of the proposed filter is measured at 5.7 mm×7.6 mm. Measured S-parameters showed that the filter achieves a 3-dB fractional bandwidth of 55% at center frequency of 10.36 GHz, with measured insertion loss of 2.08 dB and measured return loss better than 10 dB. The measured results are in good agreement with the simulated results.
An ultra wideband (UWB) coplanar waveguide (CPW) fed rectangular monopole antenna, which is of band notched characteristic for Wireless Local Area Network (WLAN), Worldwide inter-operability for Microwave Access (WiMAX) and the C-band satellite communications, is proposed, fabricated and measured. In order to obtain the desired dual band rejections, a piece of pentagonal slotline and a pair of inverted L-shaped stubs are loaded on the CPW fed rectangular monopole antenna of enhanced impedance bandwidth. The antenna is printed on the FR4 substrate of 40 mm (width) × 41 mm (length) × 0.5 mm (thickness), and is optimized by ANSOFT HFSS. A prototype is fabricated according to the optimized parameters values, and the antenna characteristics are measured. The results show that the antenna is of UWB characteristic and exhibits band rejection of 3.2-4.25 GHz and 5.1-6.15 GHz, which covers WLAN, WiMAX, and C-band satellite communications.
This paper proposes a technique of the source location estimation with the modulated scattering technique (MST) for indoor wireless environments. The uniform circular scatterer array (UCSA) that consist of five optically modulated scatterers as array elements and a dipole antenna at the center of the UCSA is employed for estimating a source location from the impinging signal. In contrast with a conventional uniform circular array (UCA), the proposed method using the MST needs only one RF path. Also, the plane-wave assumption of the impinging signal is not necessary for an array signal processing because the proposed method is based on a phaseless measurement. Therefore, the proposed method can be applied in short-range LOS and NLOS environments that the plane-wave signal cannot be formed. A source location is estimated by using a simple estimation algorithm based on the power difference of the scattering signals modulated by two scatterers on the UCSA. The power difference is caused by different propagation losses between a source and each scatterer. The performance of the proposed method is demonstrated by measuring the angles of the incoming signals in the anechoic chamber and by comparing the estimated angles with the simulated results.
In this paper, a novel type of stacked microstrip patch antenna is presented in which fractal shaped defects have been excoriated from the patch surfaces. The antenna has been designed for dual band operation at the WLAN 2.4 GHz and 5.8 GHz frequency bands and size reduction for both the stacked patches is achieved due to the use of fractal shaped defects. The antenna was simulated using CST Microwave Studio 2010 and optimized using Particle Swarm Optimization (inbuilt in CST). The fabricated antenna's measurement results were found to be in good agreement with the simulated results.
In this paper a modified version of the multi-band multiple ring monopole antenna is proposed. The height of the new design which consists of multiple half rings is half of the original one. The modified design is more attractive for low profile applications due to its lower height. The antenna is simulated and measured. It is shown that the simulation and measurement results are in good agreement. The performance of the modified version of the antenna is compared with the original design in terms of input characteristic and far field radiation patterns. It is shown that the multiband behaviour of the modified design is similar to the original one. However, there is a frequency shift between the operating bands of the new and the original antennas. The radiation patterns of the both antennas are similar to the conventional monopole antenna in lower operating frequency bands. However, degradation in radiation patterns of the both antennas is observed as frequency increases.
This letter reports a new technique that enables simultaneous detection of concentrations of the organic and inorganic substances in a hybrid fluidic solution. The technique is based on a coplanar microwave distributed MEMS transmission line. Measurement results show that a hybrid aqueous solution with a mixture of 0 M -- 0.2 M NaCl and 0 mg/ml -- 350 mg/ml glucose can be easily detected simultaneously from measured one-port scattering parameter (S11).
Abstract－This work presents a novel broadband monopole antenna for digital video broadcasting-terrestrial (DVB-T) application. The proposed antenna consists of a multiple-ring radiating patch and a sleeve-shaped ground plane. The multiple-ring monopole is used to realize the antenna height reduction at a fixed operating frequency. It shows a wide operating 2.5:1 VSWR bandwidth of 408 MHz achieved by using an impedance-matching technique. The technique applies cutting a notch at the ground plane opposite to the microstrip line and adjusting the height of the sleeve-shaped ground. The proposed antenna can operate in the 463-871 MHz frequency range and cover the DVB-T operating bandwidth (470-862 MHz). The radiation pattern of the proposed antenna in the xy-plane is omni-directional with a peak antenna gain of 4.2 dBi.
In this paper, a miniaturized bandpass filter with controllable harmonic by using split impedance resonators is proposed. The proposed split impedance resonator is based on the theories of the basic parallel impedance formula and stepped impedance resonators (SIRs). In this way, the split impedance resonator can be effectively designed to obtain good coupling for reducing the insertion loss. Furthermore, a miniaturized bandpass filter with controllable spurious frequency is proposed. The proposed bandpass filter not only has good passband characteristics but also obtains miniaturization around 21.87% versus the traditional SIR bandpass filters.
This work presents a new technique that uses floating plate overlays to realize the open-loop resonator bandpass filter with characteristics of compact size and having four controllable transmission zeros to achieve the multispurious suppression. Three floating plate overlays are used to cover parts of the open-loop resonator filter to increase the coupling between resonators and move the transmission zeros to desired frequencies to enhance harmonic suppression. A design procedure that developed based on an equivalent circuit model of such a new type of filter is proposed. Two experimental prototypes are designed and fabricated to verify the proposed design method. The measured results agree well with the simulations. The measured insertion losses of the prototypes in passband are all less than 2 dB. One prototype is designed to suppress third, fourth, and fifth harmonics with the suppression greater than 30 dBc. Another prototype can suppress second, third, and fourth order harmonics below 20 dBc. In addition, prototype circuit areas are only about 50 percent of the conventional open-loop filter.
In this paper, a new N-way multi-frequency unequal split Wilkinson power divider (WPD) is proposed. The dividers are composed of multi-section transmission line transformers (TLT) and isolation resistors, which provide high isolation and very good input/output ports matching simultaneously at arbitrary design frequencies. To verify the validity of the design, several multi-frequency power dividers are designed and simulated. Specifically, a 3-way unequal split dual-frequency WPD operating at 900 and 1800 MHz, a 3-way unequal split triple-frequency WPD operating at 1, 2, 3 GHz, and a 4-way equal split quad-frequency WPD operating at 1, 2, 3, 4 GHz, are designed.
In this paper, a modified square monopole antenna with multi-resonance performance, for UWB applications is proposed. The proposed antenna consists of a square radiating patch with a pair of T-shaped slots and a ground plane with a pair of rectangular sleeve and a T-shaped resonator which provides a wide usable fractional bandwidth of more than 125% (3.05-13.57 GHz). By optimizing dimension of rectangular sleeves, T-shaped slots and resonator, the total bandwidth of the antenna is greatly improved. The designed antenna has a small size of 14×22 mm2. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. Simulated and experimental results are presented to demonstrate the performance of a suggested antenna.
A novel microstrip array antenna based on the meta-material zeroth-order resonator (ZOR) is presented in this paper. Considering both zeroth-order resonance and the array theory, a resonant array antenna has been designed and fabricated which has small dimensions both in length and width as well as an acceptable gain. Since the resonant frequency of the zeroth-order resonator is independent of the physical length of the resonator and determined only by LC values loaded in the resonator, therefore, antenna size can be reduced arbitrarily with no changes in the operation frequency and due to the array structure antenna gain can be enhanced. Additional benefit of the ZOR antennas is lower ohmic losses as compared to the other small antennas and hence the efficiency of the antenna is higher. The discrepancy between simulation and measurement determined by fabricating some of the simulated design and comparison between the results, has been taken into account for designing the final array. A small-sized two-elements ZOR array antenna with 50% reduction in size as compared to the conventional array with a acceptable gain and broad radiation pattern is tested at 4.25 GHz. The proposed antenna has application in radio altimeters. The commercial softwares such as CST and HFSS were utilized for design and analysis of the structure.
In this paper, a new compact dual-polarized microstrip patch antenna is proposed. The patch is of rectangular shape and fed by a gap between the patch edge and a microstrip open end. Gap feeding at the edge of a rectangular patch antenna is proposed for the first time in this paper. This method of feeding occupies a negligible space compared to other feeding methods such as a quarter-wave transformer feeder, an inset feeder, a proximity coupler, and an aperture-coupled feeder. Dual-polarized radiation is realized by feeding a rectangular patch with two orthogonal gaps. First, a single-polarized patch is designed. The impedance matching property of the gap is analyzed using an equivalent circuit. Next, starting from dimensions of the single-polarized patch, a dual-polarized patch antenna is designed by optimizing the patch length and gap width. The designed antenna is fabricated and tested. The fabricated antenna has reflection coefficient less than -10 dB, port isolation greater than 30 dB, over 14.5-15.2 GHz, and a gain of 6.2 dBi at 14.9 GHz.
Infinite reflectarrays in the X-band frequency range has been designed, and various slot configurations have been proposed to optimize the design of reconfigurable reflectarray antennas in the X-band frequency range. It has been demonstrated that the introduction of slots in the patch element causes a decrease in the maximum surface current density (J) and electric field intensity (E) and hence causes a variation in the resonance frequency of the reflectarray. Waveguide simulator technique has been used to represent infinite reflectarrays with a two patch unit cell element. Scattering parameter measurements of infinite reflectarrays have been carried out using vector network analyzer and a change in resonant frequency from 10 GHz to 8.3 GHz has been shown for a slot width of 0.5W (W is the width of patch element) as compared to patch element without slot. Furthermore a maximum attainable dynamic phase range of 314°has been achieved by using slots in the patch element constructed on 0.508 mm thick substrate with a maximum surface current density (J) of 113A/m and Electrical field intensity (E) of 14 kV/m for 0.5W slot in the patch element.
This paper proposes asymmetrical step-impedance resonators bandpass filters (ASIRs) for suppressing a wide stopband, ensuing in size reduction and ease of fabrication. The filters have been designed at the operating frequency around 2.0 GHz using half- and quarter-wavelength asymmetrical step-impedance resonators. The concept of existent odd- and even-mode characteristics is used to approve the proposed filter structure. The filter can not only suppress the unwanted signals more than 10 f0, but also produce low passband insertion loss and high return loss. A good agreement is obtained between the simulation and measurement results.
In this paper, we present a novel method to design a microstrip bandpass filter (BPF) with high selectivity and upper rejection band. The proposed coupling structure mainly composes of half-wavelength input/output (I/O) microstript lines and open-loop ring resonators. By properly selecting the coupling position between the I/O lines and resonators, the spurious response of the BPF can be well suppressed. A filter example centered at 2.4 GHz achieves a high band selectivity and a wide upper-stopband rejection greater than 20 dB from 2.7 to 6 GHz. Experimental results show a good agreement with the simulated ones.
This paper presents a coplanar composite right-left handed zeroth-order resonator (CRLH CPW ZOR) and a coplanar composite right-left handed transmission line (CRLH CPW TL). These devices are realized using an elementary cell designed in a coplanar waveguide configuration on alumina substrate. Additional lumped elements are carried out with an interdigital series capacitor and a short-circuited stub inductor as a shunt. The CRLH CPW ZOR is fabricated and analyzed using equivalent circuit modeling and three dimensional finite element method. The proposed devices are fabricated and measured. The resonator has a measured insertion loss of 2.7 dB and a return loss better than 13dB. The length of the proposed device is only 5.2 mm; this very small size compared with a traditional half wave resonator shows the interest of this kind of approach.
A new circularly-polarized (CP) sleeve antenna fed by a CPW for DTV signal reception applications is presented in this paper. The CPW-fed sleeve monopole antenna consists of square loop sleeve, CPW-fed and complementary SIR radiators. The lower and upper resonance frequencies of the desired band are controlled by the complementary SIR arms, making designs of the wide-band antenna very easy. To demonstrate the idea, the proposed antenna was designed at the band with 470-863 GHz (BW=393 MHz, 58.9%) for DTV UHF-bands. The antenna gains are varied about 2.2 to 4.0 dBi. An omnidirectional radiation property is also shown. The CP operation for the proposed design can be achieved by properly adjusting the asymmetrical radiators. The reflection coefficient, axial ratio, radiation pattern and gain of the proposed antenna were studied, and reasonable agreement between the simulated and measured results was obtained.
In this paper, direction of arrival (DOA) algorithms for Frequency Modulated (FM) point source have been implemented over a real time system. The source was a commercial FM radio station broadcasting at 89 MHz. Experiments were carried out in order to determine the location of a FM transmitter using spectral and sub-space algorithms. The complete Radio Frequency (RF) front end and Uniform Linear Array (ULA) of dipole antennas were designed at 98 MHz having bandwidth of 20 MHz covering the complete FM band. The estimated DOAs are in close agreement to each other.
A compact elliptic-function band-pass filter (BPF) is introduced using microstrip folded quasi multi-mode resonator. The prototype filter is synthesized from the two-port network and equivalent circuit models using available element value tables. To optimize the performance of the filter, electromagnetic simulation (EM) is used to tune the dimensions of the filter. The filter using dual cascaded quasi multi-mode resonators provides a very sharp cut-off frequency response with low insertion loss. It also realized a broad band pass-band, a compact size and two transmission zeros at both the lower and upper stop-bands. The filter is also evaluated by experiment and simulation with good agreement.