Showing papers in "Progress in Electromagnetics Research Letters in 2020"
TL;DR: In this paper, a dual-band antenna for the integration of LTE-R 700MHz band along with 5G (3.5 GHz) band applications for future advanced railway communication is proposed and discussed in detail.
Abstract: The goal of this paper is to design a dual-band antenna for the integration of LTE-R 700MHz band along with 5G (3.5 GHz) band applications for future advanced railway communication. A design study of the dual-band antenna is proposed and discussed in detail. An ellipse-shaped ring patch is designed for the LTR-R 700-MHz band, and the 5G (3.5 GHz) band is added by keeping the circular patch in proximity to the feed line of the antenna to make it a stacked antenna configuration. Circular patches with varying dimensions are used to increase the bandwidth at 3.5-GHz band. The antenna has a size of 180mm×60mm and is fabricated on an FR4 substrate with dielectric constant 4.4 (tan δ = 0.025). The observed bandwidth is approximately 100 MHz and 500 MHz for each frequency band respectively.
34 citations
TL;DR: The simulated and measured results are found in good agreement which demonstrates the applicability of proposed antenna for GSM 1800/WLAN/WiMAX applications in laptop devices.
Abstract: A novel multifrequency printed monopole antenna applied to GSM, WLAN, and WiMAX standards in laptop devices is developed. The novelty of the proposed monopole antenna is the simple design without using any reactive components, expensive substrate, or any additional hardware to operate in multi-band frequencies for laptop applications. It is noteworthy that the dimensions of the proposed antenna structure is only 0.105λ × 0.05λ, at lower resonating frequency 1.8 GHz, thus attaining a height of only 9 mm above the system ground. This antenna mainly incorporates an ‘F’shaped strip and a ‘C’-shaped strip together printed on an FR-4 substrate. The coaxial feeding results in the generation of three bands with measured impedance bandwidth spanned in the range of (1.74– 1.87 GHz) in lower band (fl), (2.40–2.50 GHz) in a medium band (fm), and (5.12–6.06 GHz) in upper band (fu). Furthermore, the aforementioned antenna exhibits excellent radiation performances including gain around 4–5 dBi followed by efficiency greater than 80% in all the operating bands. The simulated and measured results are found in good agreement which demonstrates the applicability of proposed antenna for GSM 1800/WLAN/WiMAX applications in laptop devices.
24 citations
TL;DR: In this article, a high gain dual band rectenna is proposed for energy harvesting applications that is designed and optimized to operate at 3.5 GHz and 5.8 GHz frequency bands.
Abstract: In this article, a high gain dual band rectenna is proposed for energy harvesting applications. A dual band antenna is designed and optimized to operate at 3.5 GHz and 5.8 GHz frequency bands. The antenna is based on a multilayer substrate structure excited by aperture-coupling feed. In order to achieve a maximum gain of the antenna in both bands, a rectangular cell optimized by genetic algorithms is etched on the radiating element (patch). This antenna was simulated and fabricated, and the results show a good agreement in both bands (3.5 and 5.8 GHz) with a high gain of 10.2 dBi and 8.92 dBi for the first and second bands, respectively. A dual-band rectifier is also designed and studied to harvest the radio frequency energy absorbed by the antenna to DC energy at these frequency bands (3.5 GHz and 5.8 GHz). This rectifier shows a good performance in terms of conversion efficiency which achieves 44% in the first band and 29% in the second band. As a result, an output voltage of 656.88 mV for a low input power of 0 dBm is observed when the rectifier operates at both bands.
21 citations
TL;DR: In this article, a new design of high sensitivity photonic crystal temperature sensor (PCTS) is investigated, which consists of two inline quasi-waveguides which are coupled to a resonant cavity.
Abstract: In this paper we investigate a new design of high sensitivity photonic crystal temperature sensor (PCTS). A square lattice of silicon (Si) rods immersed in air matrix is used as a basic structure. The designed sensor consists of two inline quasi-waveguides which are coupled to a resonant cavity (RC). The sensing principle is based on Si refractive index change caused by the variation of the temperatures over a range from 0 to 80◦C. This variation leads to an important shift in the resonance wavelength. The performance of the suggested temperature sensor has been analyzed and studied using finite-difference time domain (FDTD) method. The results show that our designed structure offers a high sensibility of 93, 61 pm/◦C and quality factor of 2506.5. Its structure is very compact with total size 115.422 μm2, which is suitable for nanotechnology based sensing applications.
18 citations
TL;DR: In this paper, a triple resonance microstrip slotted antenna element for 5G (5.15-5.875 Wi-Fi band) applications is presented, which constitutes a rectangular patch stimulated with an I-shaped slot and two shorted metallic vias.
Abstract: This study presents a triple resonance microstrip slotted antenna element for 5G (5.15–5.875 Wi-Fi band) applications. This antenna constitutes a rectangular patch stimulated with an I-shaped slot and two shorted metallic vias. This arrangement results in an enhancement of the bandwidth. The antenna features a wide impedance bandwidth (IBW) matching due to triple resonances when being properly excited by coax-probe feed. The IBW of the antenna ranges from 5–6 GHz band with three resonances at around 5.2, 5.5, and 5.8 GHz. Finally, the antenna is fabricated and measured, which displays a −10 dB IBW of 5.04–6.05 GHz (18.2%) featuring stable radiation and gain (around 7dBi). Moreover, the measurements are in good agreement with simulations. On the account of the single-layered dielectric, this antenna can be easily mounted with active electronics.
15 citations
TL;DR: In this paper, a dual-band microstrip antenna for Global System for Mobile Communications (GSM) and Worldwide Interoperability for Microwave Access (WiMAX) applications is presented.
Abstract: This paper presents a dual-band microstrip antenna for Global System for Mobile Communications (GSM) and Worldwide Interoperability for Microwave Access (WiMAX) applications. The split ring resonators structure driven antenna operates at 900 MHz and 3.3 GHz, respectively. Return losses achieved at the two resonance frequencies are 22.26 dB and 18.97 dB, respectively. The proposed antenna is developed on a cost-effective FR-4 substrate with relative permittivity 4.4, tangent loss 0.002, and partial ground plane. The bandwidths of the proposed antenna are 3.01% and 4.26%, respectively. The design and fabrication procedure along with both simulated and measured results are presented and discussed in this paper. Designed antenna delivers good performance and solution for both applications.
13 citations
TL;DR: In this paper, a broadband microstrip-to-waveguide end-wall probe transition using a semicircular loop is proposed, and a compact broadband waveguide termination is developed by combination of this microstrip to waveguide transition and a 50 Ω microstrip termination.
Abstract: A broadband microstrip-to-waveguide end-wall probe transition using a semicircular loop is proposed in this letter. The simulated 20-dB fractional bandwidth for this transition is 48.3% which could cover the whole Ka-band. Then, a compact broadband waveguide termination is developed by combination of this microstrip-to-waveguide transition and a 50 Ω microstrip termination. To reduce parasitic effects, the microstrip termination is grounded by a microstrip radial stub. The fabricated waveguide termination shows a compact size and has a return loss better than 16.6 dB from 26 to 40.8 GHz.
12 citations
TL;DR: The proposed ultrawide band (UWB) notch antenna with electromagnetic bandgap (EBG) structure for WiMAX and satellite applications is proposed and has good radiation characteristics in the required frequency bands.
Abstract: In this paper, an ultrawide band (UWB) notch antenna with electromagnetic bandgap (EBG) structure for WiMAX and satellite applications is proposed. The proposed design contains an inverted-π model slot and EBG element which create lower and upper notch frequency bands, respectively. The designed antenna is fabricated on a Rogers RT/duroid 5880 with the dimensions of 18 × 21 × 1.6 mm3 which is fed with a 50 Ω transmission line. The proposed antenna has a frequency range from 2 GHz to 12 GHz, in which lower notch covers 3.3–3.7 GHz (WiMAX), and upper notch covers 5.9–6.9 GHz (satellite uplink application). The simulated and measured proposed antenna results are in good correlation. It has good radiation characteristics in the required frequency bands.
12 citations
TL;DR: In this article, an eccentric harmonic magnetic gear (EHMG) with Halbach array is proposed, where the permanent magnets on the inner rotor and outer stator are arranged in a Halbach arrays.
Abstract: An eccentric harmonic magnetic gear (EHMG) with Halbacharray is proposed in this paper. According to the theory of magnetic field modulation and one-side effect, the permanent magnets (PMs) on the inner rotor and outer stator are arranged in a Halbach array. The PMs of inner rotor are divided into three segments per pole, and the PMs on the outer stator are divided into two segments per pole. The proposed EHMG with 15 pole pairs on inner rotor PMs and 16 pole pairs on outer stator PMs is established. The finite element analysis (FEA) is used for simulating the proposed model. The corresponding magnetic field and static torque of the EHMG are calculated. Compared with the conventional EHMG, the results show that the torque density of the proposed EHMG is substantially improved.
11 citations
TL;DR: In this article, a microstrip ultra-wideband (UWB) bandpass filter with quad sharply notched bands and good selectivity is proposed using quad parallel defected microstrip structures (PDMSs).
Abstract: A new approach to design a microstrip ultra-wideband (UWB) bandpass filter (BPF) with quad sharply notched bands and good selectivity is proposed using quad parallel defected microstrip structures (PDMSs). The initial UWB BPF comprises interdigital coupled lines and an E-shaped multiple-mode resonator (EMMR) to achieve two transmission zeros on both sides of the passband thus to improve skirt selectivity. Then, four PDMSs are introduced, which have the properties of achieving four band-notched characteristics and provide high degree of adjusting freedom. To validate the design theory, a new microstrip UWB BPF with four notched bands respectively centered at 5.3, 5.9, 6.4, and 7.4 GHz is designed and fabricated. Both simulated and experimental results are provided with good agreement. The designed methodology is very efficient and useful for filter synthesis though the design principle is simple.
11 citations
TL;DR: In this paper, a 16-tupling frequency system for millimeter-wave generation using cascaded arrangement of parallel Mach-Zehnder modulators is presented, where parallel MZMs work as a modulator with ultra-high extinction ratio, and the system has radio frequency spurious sideband suppression ratio ≥ 10 dB for modulation range of 2.79 to 2.86.
Abstract: A 16-tupling frequency system for millimeter-wave generation using cascaded arrangement of parallel Mach-Zehnder modulators is presented in this paper. Parallel non-ideal Mach-Zehnder modulators are used to realize a Mach-Zehnder modulator (MZM) with an ideal splitting ratio of 0.5. Hence, parallel MZMs work as a modulator with ultra-high extinction ratio. A 5GHz radio frequency signal is 16-tupled to 80 GHz with optical sideband suppression ratio of 64 dB and radio frequency spurious sideband suppression ratio of 31 dB. The system has radio frequency spurious sideband suppression ratio ≥ 10 dB for modulation range of 2.79 to 2.86. Further, optical sideband suppression and radio frequency spurious sideband suppression ratios are independent of extinction ratio of MZMs.
TL;DR: The integrated design of 4G LTE and mmWave 5G antennas based on a low cost substrate is proposed for mobile terminals and orthogonal pattern diversity is achieved for the usage of smartphone in both portrait and landscape modes.
Abstract: The integrated design of 4G LTE and mmWave 5G antennas based on a low cost substrate is proposed for mobile terminals. The 4G LTE antenna is designed along with the millimeter wave 5G antenna element, and this integrated module is mounted orthogonally to cater for smartphone applications. The 4G LTE module consists of two orthogonally placed compact asymmetric coplanar strip (ACS) fed antennas which caters to LTE1900, LTE2300, and LTE2500 bands. ACS-fed antennas operate from 1.8 to 2.7 GHz with a reasonable gain ranging between 1.5 and 2.9 dBi. The mmWave 5G antenna module comprises two compact Vivaldi antennas with wideband operational bandwidth ranging from 23 to 39 GHz. Each mmWave 5G antenna attains 1-dB gain bandwidth of 47.6% indicating high radiation bandwidth across the operating frequency band. Orthogonal pattern diversity is achieved for the usage of smartphone in both portrait and landscape modes. The whole antenna architecture is accommodated to the panel of height 6 mm inside a fabricated three dimensional mobile phone case. Simulated and measured results are presented with technical justification.
TL;DR: In this paper, the authors used identical subarrays to partition a large rectangular aperture and optimized the element positions by particle swarm optimization (PSO) to obtain low sidelobe levels.
Abstract: Partitioning large arrays into subarrays can reduce system cost. In this paper, we use identical subarrays to partition a large rectangular aperture. The periodical structure in a large array is broken down by changing the orientations of the subarrays. In each subarray, the element positions are optimized by particle swarm optimization (PSO) to obtain low sidelobe levels. In order to reduce the coupling among the elements, the minimum element distance measured in Euclidean space is restricted in the procedure of optimization. And a modified PSO is proposed to solve the optimization problem with this constraint. Better results can be obtained than the element distance constraint measured in Chebyshev space. This simple but efficient subarray design method is demonstrated through several numerical simulations.
TL;DR: In this article, a simple-structured dual circularly polarized (CP) antenna design for 5G front-end systems is presented, where the antenna configuration consists of a crescentshaped slot radiator fed by a pair of rectangular 50-Ohm microstrip lines.
Abstract: This paper introduces a new simple-structured dual circularly polarized (CP) antenna design for fifth-generation (5G) front end systems. The antenna configuration consists of a crescentshaped slot radiator fed by a pair of rectangular 50-Ohm microstrip lines. The antenna is designed on an FR-4 dielectric substrate with an overall size of 48 × 48 × 1.6 mm3 to operate at 3.5 GHz, a 5G candidate band. A wide dual CP characteristic supporting both left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP) is achieved in the frequency of 3–4.2 GHz. In addition, the mutual coupling (S21) between two ports of the proposed antenna is better than 15 dB. A prototype sample of the proposed design is fabricated and measured to validate the design concept. The antenna offers sufficient efficiency, gain level, and axial ratio bandwidth which make it suitable for different 5G front end applications such as cognitive radio, base station, satellite communications, imaging, and radar systems.
TL;DR: A magnetic field propagation model is developed to show MI communication’s different performances in the near-field and the far-field, and develops rigorous models to capture the multipath fading, the penetration efficiency through inhomogeneous media, and the attenuation loss in lossy media.
Abstract: Ultra-reliable and low-power wireless communications are desirable for wireless networking in extreme environments such as underground tunnels, underwater, and soil. Existing wireless technologies using electromagnetic (EM) waves suffer from unpredictable multipath fading and blockage. The recent development of magnetic induction (MI) communication provides a low-power and reliable solution, which demonstrates negligible multipath fading, high penetration efficiency, and low attenuation loss in lossy media. However, existing works neglect the fact that MI communication only demonstrates such advantages in the near-field, beyond which the MI communication converges to electromagnetic wave-based communication and all the aforementioned advantages disappear. This letter develops a magnetic field propagation model to show MI communication’s different performances in the near-field and the far-field. We develop rigorous models to capture the multipath fading, the penetration efficiency through inhomogeneous media, and the attenuation loss in lossy media. The results show that although MI communication can provide reasonable signals in the far-field, it only demonstrates negligible multipath fading, high penetration efficiency, and low attenuation loss in the near-field.
TL;DR: In this paper, the authors used polyvinylidene fluoride (PVDF) as insulating matrix and graphite (Gr) as a filler to develop conducting composite films using solvent casting technique.
Abstract: Graphite receives tremendous attentions as filler for conducting composite due to its low cost and high electrical conductivities. In this work we use polyvinylidene fluoride (PVDF) as insulating matrix and graphite (Gr) as a filler to develop conducting composite films using solvent casting technique. The dielectric properties of the developed PVDF-Gr films were analysed for the frequency range of 100 kHz to 10 MHz. The morphology of the obtained films was investigated by scanning electron microscopy. The EMI shielding properties of the PVDF-Gr composite films were evaluated theoretically using ε′, tan δ, and σ in the desired radio frequency region. Mechanical strength of the films was tested by universal testing machine. Due to advantages such as light weight, flexibility, and low cost the developed film with the thickness of ∼ 0.15 mm had very good potential to be used for fabricating electromagnetic compatible electronic devices.
TL;DR: An optimized dual-band notched antenna for Ultra-Wide Band applications, using the Genetic Algorithm, shows good performance and accuracy compared to conventional approaches.
Abstract: An optimized dual-band notched antenna for Ultra-Wide Band applications, using the Genetic Algorithm (GA), is presented. By optimizing a Defected Ground Structure (DGS) in the ground plane of the UWB antenna, two notches are created at the desired frequency bands of 3.5 GHz and 5.8 GHz, respectively. A good agreement between the measurement and simulation results is observed. The optimized DGS shows good performance and accuracy compared to conventional approaches.
TL;DR: In this paper, the joint direction of departure (DOD) and direction of arrival (DOA) estimation of coherent targets in bistatic multiple-input multiple-output (MIMO) radar under the presence of spatially correlated noise is investigated.
Abstract: This paper investigates the joint direction of departure (DOD) and direction of arrival (DOA) estimation of coherent targets in bistatic multiple-input multiple-output (MIMO) radar under the presence of spatially correlated noise. Based on electromagnetic vector sensors at both transmitter and receiver of MIMO radar, a preprocessing method, namely polarization difference smoothing, is proposed to remove the coherence between targets and to suppress the spatially correlated noise. Then DODs and DOAs are estimated using the ESPRIT method. Further, this paper develops a simple approach for pair-matching between the estimated DODs and DOAs. Simulation results are compared with the receive polarization smoothing and transmit-receive polarization smoothing methods available in literature. Results show that the proposed approach improves the performance significantly.
TL;DR: In this paper, a compact substrate integrated waveguide (SIW) filter based on composite right/lefthanded (CRLH) resonator units is implemented, which works at a center frequency of 5.8 GHz with 200 MHz bandwidth.
Abstract: A compact substrate integrated waveguide (SIW) filter based on composite right/lefthanded (CRLH) resonator units is implemented in this paper. The filter is composed of two CRLH resonator units serially connected by a SIW transmission line unit. The structure of the filter and equivalent circuit transmission behavior are analyzed, and a novel design method by optimizing the length and width of the interdigital metal slots to decrease the filter operation frequency is proposed. To further demonstrate the design theory and performance of the proposed filter, the filter was designed and fabricated on an RT6010 dielectric material. The measurement results show that the proposed filter works at a center frequency of 5.8 GHz with 200 MHz bandwidth The insertion loss is 2.3 dB, and the filter size is only 10 mm × 7.4 mm.
TL;DR: In this paper, a miniature multiple input multiple output (MIMO) ultra wide band (UWB) antenna with dual notched characteristics is proposed, which incorporates a tapered microstrip feed line with two radiating patch structures procured by the incorporation of two ellipses with a circle and reduced ground structure.
Abstract: A novel, miniature multiple input multiple output (MIMO) ultra wide band (UWB) antenna with dual notched characteristics is proposed. The antenna incorporates a tapered microstrip feed line with two radiating patch structures procured by the incorporation of two ellipses with a circle and a reduced ground structure. The proposed antenna is printed on an FR-4 substrate having a concise size of 40 × 22 mm2 to cover −10 dB bandwidth of 3.18–11.26 GHz with fractional bandwidth of 112%. The two notched bands 3.31–3.99 GHz for WiMAX and 4.97–5.93 GHz for WLAN accomplished by two T-shaped parasitic structures are etched above ground plane and inverted U-shaped slots etched on radiating patch, respectively. The isolation of < −15 dB is realized by inserting a T-shaped stub in between two patch elements. The measured MIMO diversity characteristics are the evidence of that the proposed antenna is appropriate for portable wireless applications.
TL;DR: In this article, a dual-band-notched CPW-fed UWB MIMO antenna with mutual coupling reduction characteristics is presented, and the measured impedance bandwidth with S11 < −10 dB is 137% from 3 GHz to 16 GHz.
Abstract: A novel dual band-notched CPW-fed UWB MIMO antenna with mutual coupling reduction characteristics is presented in this paper. The proposed antenna uses CPW feeding to expand the antenna bandwidth. The measured impedance bandwidth with S11 < −10 dB is 137% from 3 GHz to 16 GHz. The overall size of the antenna is 46mm × 32mm × 1.6 mm. In order to achieve dual bandnotched characteristics, a cup-shaped branch is added to the grounding plate, and a step impedance resonator (SIR) is added to the microstrip line. By adding periodic strip branches on the back of the antenna, the mutual coupling between the two antennas is significantly reduced, which meets the requirements of practical applications. In addition, the proposed antenna has a compact size and can provide a stable radiation pattern, which is suitable for UWB communication systems.
TL;DR: In this article, two pairs of face-to-face symmetrical spiralshaped DGSs are added to the ground planes of a CPW main transmission line to improve the passband performance of the filter, which has a 10.1% bandwidth with a return loss better than 10 dB from 3.35 GHz to 3.71 GHz.
Abstract: A CPW (coplanar waveguide) bandpass filter based on spiral-shaped DGSs (defected ground structures) which can be used in the 5G band is proposed. Two pairs of face-to-face symmetrical spiralshaped DGSs are added to the ground planes of a CPW main transmission line. A cross-shaped notch is adopted in the central strip of the CPW main transmission line to generate the passband, while two m-shaped DGSs are brought in to improve the passband performance of the filter. The measured results show that the central frequency is 3.54 GHz, and the 3-dB bandwidth is from 3.29 GHz to 3.79 GHz. The filter has a 10.1% bandwidth with a return loss better than 10 dB from 3.35 GHz to 3.71 GHz, and the insertion loss is less than 2.0 dB in the passband. Besides, there are two transmission zeros near the passband at 2.45 GHz and 4.81 GHz, which can improve the stopband rejection.
TL;DR: In this paper, the authors proposed a wideband low profile dual-polarized antenna based on the use of an artificial magnetic conductor (AMC) reflector, which consists of nine × 9 square patches.
Abstract: A wideband low-profile dual-polarized antenna based on the use of an artificial magnetic conductor (AMC) reflector is proposed. The AMC reflector consists of 9 × 9 square patches. In order to obtain wide impedance and gain bandwidths, the antenna consists of four printed dipoles: two dipoles are used as a radiator of horizontal polarization, and two dipoles are used as a radiator of vertical polarization. A simple excitation scheme without balun is used for dipoles feeding. A low profile of 0.068λL is realized (λL is the wavelength at the lowest operating frequency). Simulation and measurement results show that the proposed antenna has a 40% impedance bandwidth, a 40% 3-dB gain bandwidth, and a port isolation of less than −30 dB.
TL;DR: In this paper, a novel ultra-wideband and thin metamaterial absorber is proposed, which consists of a single FR4 layer, metallic ground, and four metallic spirals.
Abstract: Electromagnetic interference (EMI) is a crucial problem, and for solving this problem, absorbers especially very thin absorbers are used. Factors like frequency increasing in a device, high integration in electronic systems, higher power densities, and decreasing the size and thickness of PCB make it crucial. So, a novel ultra-wideband and thin metamaterial absorber is proposed in this paper. The absorber consists of metamaterial unit cells, which have a single FR4† layer, metallic ground, and four metallic spirals. A one hundred ohms SMD‡ resistor is placed between two of the spirals. The size of the unit cell is 5.85×5.85×3.2 mm3. The proposed absorber is ultra-thin (λ0/10), and the absorption occurs over a wide incident angle [0◦–40◦]. The reflection is less than −12 dB in [6.5 GHz–12 GHz], and the absorption is more than 94% in this bandwidth. The structure is fabricated, and the outcomes of simulation and measurement are compared with each other. The values of front to back ratio of the fabricated measurements are −12.8, −7.31, and −15.36 dB at 8, 10, and 12 GHz, respectively. The values obtained from simulation are −13, −9.4 and −14 dB, respectively. There is a good agreement (accordance) between the simulation and measurement results of this absorber.
TL;DR: In this paper, a novel antenna composed of inductors (L) or capacitors (C) on an air-substrate was presented for the next/fifth generation (5G) frequency spectrum.
Abstract: The extending applications for mobile computing have experienced immense progress over the previous decade. However, this has ultimately influenced the shortage of bandwidth. Therefore, to fulfill the consumers’ demand, inexpensive antennas need to be uniquely designed for the next/fifth generation (5G) frequency spectrum. Consequently, this paper presents a novel antenna composed of inductors (L) or capacitors (C) on an air-substrate. Zinc (Zn) and copper (Cu) materials are utilized to fabricate the lumped LC resonator prototype. The effects of antenna’s and substrate’s thickness on resonant frequency or bandwidth have been studied. The finalized configuration engaged 1113 sq. mm area and operated at 28 GHz with approximately 3 GHz bandwidth. At resonant frequency, the system demonstrates peak gain and efficiency values of 10.6 dBi and 91%, respectively. The core objective of this paper is to report an antenna featuring simple and economical design along with premium results for 5G mobile terminals.
TL;DR: This research work introduces a compact dual composite right/left handed (D-CRLH) unit cell structure for filtering power divider (FPD) application that offers miniaturization and the position of resonance frequency independently controlled by series parameter only because of shorted structure.
Abstract: This research work introduces a compact dual composite right/left handed (D-CRLH) unit cell structure for filtering power divider (FPD) application. The D-CRLH unit-cell consists of an interdigital capacitor with two shorted fingers in series. It contains a meander line, a rectangular stub, and a via in shunt, both series and shunt elements provide filtering response as a bandpass filter. This design has been developed on dielectric material of thickness 1.6 mm, usually called as Epoxy glass substrate (FR-4). The transmission line of length λg/4 of a Wilkinson power divider has been replaced with a D-CRLH unit cell to reduce the size of proposed structure more than 60%. Another advantage of using a D-CRLH structure is the position of resonance frequency independently controlled by series parameter only because of shorted structure. The series chip resistor has been utilized to improve the isolation at resonance in between output ports. It offers miniaturization with electrical footprint area of 0.15λg × 0.27λg (11.4mm× 20.4 mm), here λg represents the guided wavelength at resonance frequency of 2.5 GHz.
TL;DR: In this paper, the authors discuss ρA and 0[E×B and show that the former is preferable to the latter for several reasons which are discussed in detail and by example.
Abstract: In this paper, we discuss two well-known definitions of electromagnetic momentum, ρA and 0[E×B]. We show that the former is preferable to the latter for several reasons which we will discuss. Primarily, we show in detail—and by example—that the usual manipulations used in deriving the expression 0[E×B] have a serious mathematical flaw. We follow this by presenting a succinct derivation for the former expression. We feel that the fundamental definition of electromagnetic momentum should rely upon the interaction of a single particle with the electromagnetic field. Thus, it contrasts with the definition of momentum as 0[E × B] which depends upon a (defective) integral over an entire region, usually all space.
TL;DR: In this article, a triple-band patch antenna operating at 0.9, 1.8 and 2.4 GHz is presented, which has the advantages of the easy control of each resonant frequency and relatively simple antenna structure.
Abstract: A triple-band patch antenna operating at 0.9, 1.8 and 2.4 GHz is presented. The triple-band characteristic is realized by using a radiating patch and two meander lines achieved by embedding slots in its radiating patch. According to the current distribution of the radiating patch, the locations of two meander lines are chosen. The proposed antenna has the advantages of the easy control of each resonant frequency and relatively simple antenna structure. The measured −10 dB impedance bandwidths are 30, 40, and 30 MHz at 0.9, 1.8, and 2.4 GHz, respectively. The simulated and measured radiation patterns and gains are also presented and discussed.
TL;DR: In this article, the symmetric elliptical grooves are adopted to suppress high-order modes and realize the desired phase difference in an X-band polarizer prototype with length of 91 mm.
Abstract: The available polarizers either cannot afford gigawatt-class high-power microwave applications or are large in length. In this letter, a novel grooved polarizer is proposed. The grooves are proposed to be created in an over-mode circular waveguide to improve the power capacity and bandwidth. Moreover, the symmetric elliptical grooves are adopted to suppress high-order modes and realize the desired phase difference. An X-band polarizer prototype is designed and manufactured with length of 91 mm. Simulated results show that the power capacity of the polarizer is more than 1.5 GW. Measured results in accordance with simulations show that the axial ratio is less than 3 dB from 8.6 to 12.2 GHz, with relative bandwidth of 34.6%. The measured return losses are better than −12.7 dB in the same frequency range.
TL;DR: In this paper, a compact four-element multiple-input-and-multiple-output (MIMO) antenna system is proposed based on substrate-integrated-waveguide (SIW) cavities.
Abstract: A compact four-element multiple-input-and-multiple-output (MIMO) antenna system is proposed based on substrate-integrated-waveguide (SIW) cavities. By bisecting a square SIW cavity, two rectangle half-mode cavities with opened edges are formed. They are arranged side by side sharing a row of metallic vias. Then two narrow T-shaped slots are etched along symmetry planes to divide these two cavities into four quarter-mode sub-cavities. Excited by feeding ports, four antenna elements with compact size are constructed, which radiate incident wave through opened cavity edges and etched slots. Moreover, antenna isolation can be easily improved by adjusting slot length though these elements interconnect. A prototype with the cavity size of 0.22λ0 × 0.86λ0 × 0.04λ0 has been fabricated. The fabricated MIMO antenna system exhibits the center frequency of 3.51 GHz, port isolation of 14 dB, envelope correlation coefficient of 0.03, peak gain of 4.9 dBi, and high efficiency of 77.4%. The compact size and effective isolation improvement make the proposed design attractive for practical applications.