A novel dual-polarized printed AMOS antenna with high isolation operating at 5.4 GHz is proposed. The horizontal and vertical polarizations have similar radiation patterns in horizontal plane with the HPBW over 90°. In the frequency range of 5.2 GHz-5.6 GHz, the vertical polarization antenna and horizontal antenna have the gain above 7.4 dB and 10 dB, respectively. The S21 between the two input ports of the dual-polarized AMOS antenna is lower than -40 dB.
We study electromagnetic wave propagation in a system that is periodic both in space and in time, namely, a discrete (``lumped'') transmission line with capacitors (``varactors'') that are modulated in time harmonically. These periodicities result in exotic electromagnetic band structures that are periodic in the angular frequency ω and in the phase advance ka of the wave. Depending on the strength of modulation m and the reduced modulation frequency Ω/ω0 (where ω0 is the resonant frequency of a unit cell of the transmission line), this band structure can display frequency or wave vector band gaps, both, or neither. Moreover, minor changes in or the modulation strength can control the aperture or closure of a gap and even transform a k-gap to an ω-gap. Such phase transitions are intimately associated with exceptional or critical points in the (ω, k, Ω, m) space.
In recent years, permanent magnet synchronous linear motor (PMSLM) has gained tremendous momentum in industry, especially in the high-precision field. This is mainly because it has the advantages of small size, high control precision, reliable operation. However, due to the special structure of linear motor, the control strategy of rotating motor cannot be directly applied to PMSLM. Three control strategies for reducing loss and improving efficiency of PMSLM are proposed in this paper. Firstly, the mathematical model of PMSLM is established and the loss model and efficiency equation are established. Secondly, we adopt the loss model control strategies of id=0, maximum thrust current ratio and direct thrust are used to optimize the efficiency of the motor. Finally, simulation experiments are carried out for the three proposed optimization strategies, and the effects of initial speed and load on motor efficiency are analyzed. The effectiveness of the three loss model control strategies proposed in this paper is fully verified by the simulation results, and it is found that the loss model control strategy of id=0 has the most obvious efficiency improvement.
This paper addresses the design and fabrication of an embroidered textile RFID tag antenna. The main feature of this design is that we have embroidered an RFID chip on the textile support which avoids the use of metallic wires or soldering. The modeled equivalent circuit of the tag is presented to get physical insight into RFID tag antenna design. The detailed results given in this paper include the effect of the bending and the human body proximity on the antenna performance. It is shown that the bending does not introduce a conspicuous effect on the tags read range while the dissipative characteristics of the human body cause a gain and read range reduction. The proposed design may find applications in wearable devices dedicated to health monitoring applications.
This article reports a single layer tri-band bandpass, polarization insensitive Frequency Selective Surface (FSS). The unit cell is designed by considering different square loop elements and cross dipole element to pass Wi-Max and WLAN frequency range with low loss. Three different shapes of loops and one cross dipole are arranged in a way that gives a triple-band-pass characteristic from the proposed structure. These loops and dipole are designed to pass Wi-MAX (2.5-2.7 GHz, 3.4-3.6 GHz) and WLAN (center frequency, 5.5 GHz) bands. The structure performance is independent of incidence angle of wave due to its symmetrical geometry which makes the design polarization insensitive and achieves good angular stability. A 14x14 array of proposed unit cell is realized and measured. The proposed FSS achieves a 3 dB transmission bandwidth of 25% at 2.6 GHz, 65.6% at 3.5 GHz and 65.6% at 5.5 GHz. The advantage of the proposed design is that it has a simple and compact geometry fabricated on a low-cost substrate and achieved tri-band band pass response with a wide angular stability.
This paper presents the design and measurements of a dual-band Triple H-Defected Ground Structure (Triple H-DGS) antenna. DGS has proven to be successful in the design of multiband antennas; however because of the lack of a standard approach, the determination of the exact position of the Triple H-DGS requires rigorous and lengthy numerical computations. The aim of the current work is to present a state-of-the-art innovative, efficient, and accurate solution based on Machine Learning (ML) techniques. The design is based on Substrate Integrated Waveguide (SIW) technology which provides low cost, small size, and convenient integration with planar circuits. The antenna is fabricated on a Roger 5880 substrate with a thickness of 1.6 mm, relative dielectric constant of 2.2, and tangent loss of 0.0009. The proposed antenna was developed using a hybrid solution based on CST Microwave Studio assisted by ML, and the fabricated prototype was measured using both ROHDE & SCHWARZ ZVB20 network analyser and an anechoic chamber setting. The measurement results show good agreement with the simulation. The antenna demonstrates a dual-band performance at centre frequencies of 12.67 GHz and 14.56 GHz, for which the respective antenna gains are 7.03 dBi and 7.38 dBi, and antenna directivities of 7.77 dB and 8.13 dB, respectively. The antenna total efficiencies are 95.25% and 95.60%, at the corresponding centre frequencies. The developed ML based technique shows good accuracies of about 98% in the determination of the DGS position and saves more than 99% of the computational time. The developed antenna is compact, simple in structure, and can be used for different applications in the Ku band.
In the present day scenario, the need for 5G technology is increasing daily, so we design a reconfigurable antenna working in the millimeter-wave range (25 GHz-30 GHz). The antenna is designed using HFSS software, and the antenna is loaded with compact planar metamaterial. This design includes 9 unit cells arranged in a 3 x 3 array, and each unit cell is made up of a hexagonal patch surrounded by a split ring resonator. Apart from this two-unit cells are connected using pin diodes. By operating these two pin diodes in different modes we get four different characteristics. The designed antenna radiates at 27 GHz with a gain of 3.75 dB to 4 dB. The designed antenna is compact and easy to fabricate with dimensions of 30 mm x 23 mm.
Controlled mutual attraction or repulsion, by the aid of light beam, between two or more particles, is regarded as the reversal of optical binding force. It has emerged as an important tool in the area of optical manipulation, facilitating clustering or aggregating between homodimer and heterodimer arrangements of particles. Despite a vast array of works being done in this area, dielectric-plasmonic hybrid dimer pair has not received any attention yet. To the best of our knowledge, in this letter, we have provided the very first proposal of a generic way to attain the controlled broadband reversal of optical binding force between dielectric and plasmonic hybrid dimer pair. A simple optical setup consisting of a plasmonic substrate placed underneath the hybrid dimer pair has been proposed, where the reversal of optical binding force can be attained by the incidence of a non-structured laser beam in both near- and far-field regions. Furthermore, we have demonstrated that the magnitude of this binding force can be enhanced, simply by altering the angle of incidence of the source of illumination. The force reversal has been attained based on two physical phenomena - mutual attraction and repulsion between the charges formed within the hybrid pair and the reversal of current density in the plasmonic object.
The object of this paper is a permanent magnet synchronous linear motor (PMLSM), whose control method is based on a model-referenced adaptive system (MRAS), and it analyses the speed identification of a permanent magnet synchronous linear motor without position sensors. The article proposes a new model-referenced adaptive method, which utilises a sliding-mode variable structure control method (SMC), to replace the PI control algorithm utilised in conventional model-referenced adaptive algorithm. The control system of the PMLSM is therefore designed and studied based on the change of the adaptive law in model-referenced adaption. the mathematical model of the PMLSM itself is chosen as the reference model, and the feedback magnetic chain model of the motor output is chosen as the adjustable model, replacing the conventional current model and simplifying the control algorithm. The sliding mode surface of the sliding mode variable structure control algorithm is constructed using the reference model and the output error of the adjustable model. Through theoretical analysis and simulation models built by MATLAB/Simulink simulation software, the simulation results show that the designed PMLSM speed induction-free control system MRAS speed observer based on the sliding mode variable structure has strong robustness and excellent dynamic static performance. The advantages verified by the new algorithm achieve the experimental purpose of the expected assumptions.
In this paper, a Substrate Integrated Waveguide (SIW) band pass filter loaded with a square Complementary Split Ring Resonator (CSRR) etched with Defected Ground Structure (DGS) is proposed. SIW is a promising candidate for the design and development of various microwave and millimeter wave components useful in communication systems. Due to the evanescent mode propagation and TE10 mode of the cavity, dual band (5.57/7.84 GHz) filtering is achieved with a 3-dB fractional bandwidth (FBW) of 6.8% and 4.1% respectively. The dual bands achieve a low insertion loss of 1.8 dB and 2 dB respectively. Cursor head DGS improves the out of band rejection to a greater level. The configuration is investigated with its corresponding circuit and simulated using Computer Simulation Technology (CST) software. The prototype is fabricated using a Rogers substrate with εr of 3.5 and tested. This prototype finds its application in C band satellite communication systems. The measured results are consistent with the simulated ones.
In this paper, a low profile Frequency Selective Surface is presented, for obtaining electromagnetic shielding in four distinct frequency regions. The designed structure consists of three rectangular strips Resonators, Jerusalem cross in the top side and diagonal metallic strips on bottom side of the dielectric. The proposed structure provides electromagnetic shielding at 9.9 GHz, 12.3 GHz, 13.5 GHz, and 16.4 GHz frequency regions. Besides these frequency regions, we also obtain five transparent windows suitable for telemetry application. The prototype of the proposed structure is fabricated. It is observed that the measured results are nearly similar to simulated results because of minor fabrication errors. Furthermore the proposed low profile structure can be deployed for applications like radoms, spatial filters, antenna reflectors and RCS reductions.
In this paper, a full-360° reflection-type phase shifter (RTPS) using a trans-directional (TRD) coupler with multi-resonance loads is presented. It features the characteristics of wide bandwidth, small size, and wide phase shifts with a compact structure and inherent DC blocking. Influences of the multi-resonance loads on the phase shifts and insertion losses of the RTPS are analyzed, and design procedures are given for guidance. For validation, a prototype is designed at 2 GHz. The overall size is 0.56λg × 0.17λg. Measured results show a bandwidth of 20% under the criterion of more than 10-dB return loss. Meanwhile, a relative phase variation of 425° with a maximum insertion loss of 3.6 dB is achieved when the varactor capacitance is varied among 0.35 pF~3.2 pF.
A Negative Group delay (NGD) triple passband filter with a lossy Meander Step Impedance Resonator (MSIR) is introduced in this article. The size miniaturization technique by increasing the number of meander turns is presented. In the process of filter design, the calculation of the total inductance value of the meander section is discussed in a simplified way. At the same time, the electrical and physical lengths of each section of meander resonator are calculated. The proposed filter has three passbands at 2.4, 5.0, and 7.4 GHz. The Group Delay (GD) in the three pass bands is -2.5 ns, -2.1 ns, and -2.0 ns, respectively. The more the number of meander turns is, the more the NGD will be. The proposed design is well equipped to be used in feed-forward and feed-back power amplifier applications. The frequency response exhibits satisfactory Return Losses (RLs) of -24, -25, and -22 dB at these three passbands. Four Transmission Zeros are generated at 3.35, 3.98, 6.2, and 8.31 GHz using an absorptive Folded SIR (FSIR) structure which improve the stopband performance. The overall dimension of the filter is (20.7 x 12) mm = (0.16 x 0.09)λg.
A wideband interdigital Metal-insulator-metal (MIM) capacitor is created and built in a two-layer low temperature co-fired ceramic (LTCC) substrate. To reduce the amount of stopbands and eliminate unexpected spurs which restrict the bandwidth, short-interconnection that interconnects the open ends of interval fingers is proposed. The increment of bandwidth and capacitance of the proposed interdigital MIM capacitor is 206% and 25%, respectively. The proposed interdigital capacitor has a wider frequency applicational range and a compact size of only 8.2×6.2 mm. Performance discussion and comparisons are also carried out.
In this paper, a dipole antenna is investigated for 5G New Radio portable devices. This antenna adopts the characteristics of multiple mode resonance. Then, by adjusting the spacing between dipole pairs, the antenna has a good impedance match in a wide frequency band. The -10 dB impedance bandwidth of the antenna is 2.31-5.34 GHz (79.2%). In the operation frequency band, the maximum gain and average gain of the antenna are 8.68 dBi and 4.67 dBi, respectively. It can be used in the 5G Sub-6 GHz NR frequency bands n7/n38/n41/n77/n78/n79 and also compatible with WLAN/WiMAX band.
A four-element multiple-input multiple-output (MIMO) antenna based on a modified Complementary Split Ring Resonator (MCSRR) is presented in this paper for dual-band 5G smartphone applications. An inverted L-shaped radiator is used with MCSRR as an open stub in the ground, where MCSRR is responsible for dual operating bands and enhances the impedance matching. The MCSRR as an open stub in the ground plane creates a notch band that minimizes the interference in 5G wireless communication. The four elements of the antenna are placed in such a way that minimum isolation between antenna elements is obtained, 16.5 dB, without any decoupling, whereas more than 20 dB isolation is achieved by using T-shaped decupling. The antenna achieves dual 10 dB bandwidths from 3.40 GHz to 3.625 GHz and from 3.90 GHz to 4.525 GHz. Envelop correlation coefficient (ECC) is extracted from far-field results to analyse the MIMO antenna performance in practical design consideration.
An infrared (IR) pyroelectric detector for applying to the terahertz (THz) waveband that uses diffraction limited focusing of the THz beam on the sensitive area of the detector is studied. The signal to be detected is coupled to the optical window of the detector through a two-wavelength diameter polytetrafluoroethylene spherical particle-lens based on the terajet effect. We have experimentally demonstrated an enhancement of the IR detector sensitivity by 5.6 dB at 0.2 THz without degradation of the noise equivalent power value. The results show that the proposed method could be applied to increase the sensitivity of various commercial IR sensors in the THz range, requiring no modification of the internal structure and may be applied also to acoustics and plasmonics.
The tapered waveguide as a microwave plasma excitation structure is widely used in the industrial field. However, it needs high input microwave power to ignite and sustain plasma because its electric field is not sufficiently focused in the discharge area. In order to solve this problem, this paper proposes a novel microwave plasma source based on a ridged waveguide. The structure of the proposed microwave plasma source is optimized to focus the electric field in the discharge region by electromagnetic calculations before the plasma excitation. Then, the equivalent circuit model is used to analyze the impedance matching characteristics of the novel device after the plasma excitation. In order to validate this device, a microwave plasma system is built to measure the plasma exciting power and sustaining power in both air and argon at atmospheric pressure. The simulation and experiment are carried out in both tapered waveguide and the proposed device. Simulation results show the electric field of the ridged waveguide is 1.9 times of that of the tapered waveguide when the input power is 1500 W. Moreover, in the experiments, the exciting power and sustaining power of the air and argon plasma in the novel device are lower than those of the tapered waveguide at different gas flow rates.
A compact ultra-wideband Multiple-Input-Multiple Output (MIMO) orthogonal microstrip fed linear tapered slot antenna (LTSA) is planned for frequency notched applications. The projected MIMO antenna comprises of two indistinguishable linear tapered slot antennas excited by two orthogonal microstrip feeds. In this paper, double split-ring resonators (DSRRs) are suggested to develop the isolation between two linear tapered slot antenna elements. A quarter wavelength spur line is entrenched on the feeding part of the micro-strip antenna to attain the notch frequency. The L-shaped spur line adds to the notch frequency at 5.5 GHz targeted to dodge interference from 5-6 GHz WLAN band. The planned antenna is fabricated and labelled in terms of impedance and radiation parameter measurements, compliant with that of properties achieved from full wave simulation. The antenna has congruous gain and well-built radiation pattern. Radiation pattern portrayal confirms high gain in the end-fire direction.
This article reports the development and test of a radio-propagation measurement system based on an 8-bit software-defined radio. Tests are performed in an urban area at the frequency of 733 MHz and compared with numerical prediction from the Altair WinProp commercial suite. The system is portable (1.2 kg), low-cost, based on non-proprietary open-source tools and has the capability of tracking the GPS coordinates of the measured points. Frequency limit of the system is bounded by the software-defined radio in use, and the limit of this present case spans 24 MHz to 1700 MHz. The integrated system does not need user intervention after its initial setup can be operated autonomously.
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