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Showing papers on "Return loss published in 2016"


Journal ArticleDOI
TL;DR: A dual-polarized hybrid eight-antenna array operating in the 2.6 GHz band for 5G communication multi-input multi-output (MIMO) operation in the smartphone is presented in this paper.
Abstract: A dual-polarized hybrid eight-antenna array operating in the 2.6-GHz band (2550–2650 MHz) for 5G communication multi-input multi-output (MIMO) operation in the smartphone is presented. The proposed hybrid antenna array elements are symmetrically placed along the long edges of the smartphone, and they are composed of two different four-antenna array types (C-shaped coupled-fed and L-shaped monopole slot) that exhibit orthogonal polarization. Therefore, coupling between the two antenna array types can be reduced, and the MIMO system performances are enhanced. A prototype of the proposed eight-antenna array is manufactured and measured. A good impedance matching (10 dB return loss or better), desirable cross-polarization discrimination (better than 15 dB), and an acceptable isolation (better than 12.5 dB) are obtained. Envelope correlation coefficient and channel capacity are also calculated to evaluate the MIMO performances of the proposed antenna array.

281 citations


Journal ArticleDOI
TL;DR: In this paper, a planar shared-aperture dual-band dual-circular polarization (CP) array antennas are implemented on a single-layer substrate and extended to a larger array easily.
Abstract: This paper presents a new approach to implement planar shared-aperture dual-band dual-circular polarization (CP) array antennas. The antennas can be fabricated on a single-layer substrate and extended to a larger array easily. In this approach, each array element is obtained by connecting two patches working at different frequencies directly. To form arrays with higher gain, two kinds of feed networks are described, which can be applied in systems where narrowband and wideband are needed, respectively. One is using the conventional feed network and the other is using the sequential rotation technique to further improve the CP axial ratio (AR) performance. Two prototype arrays with $4 \times 4$ elements are fabricated and tested in $X/Ku$ bands. Experimental results show that good CP characteristics are obtained, which agree well with the simulation results. For the first narrow-band prototype array, the 3-dB AR bandwidth is around 1.5% for both bands. For the second array using the sequential rotation technique, the bandwidth of return loss and AR are wider. In the lower band centered at 12.1 GHz, the ${-}10\hbox{-}\text{dB}$ return loss bandwidth is 8.3% and the 3-dB AR bandwidth is 14.2% [right-hand CP (RHCP)]; in the higher band centered at 17.4 GHz, the corresponding data are 18.9% and 14.9% [left-hand CP (LHCP)], respectively.

143 citations


Journal ArticleDOI
TL;DR: In this paper, a coplanar waveguide-fed broadband dual circularly polarized square slot antenna is presented, which consists of a square slot, two asymmetric T-shaped feed lines in orthogonal direction protrude from signal lines, and an inverted-L grounded strip with three straight strips at the corner of the slot adjacent to both the feed lines.
Abstract: A novel coplanar waveguide-fed broadband dual circularly polarized square slot antenna is presented. The antenna consists of a square slot, two asymmetric T-shaped feed lines in orthogonal direction protrude from signal lines, and an inverted-L grounded strip with three straight strips at the corner of the slot adjacent to both the feed lines. The circular polarization is obtained due to orthogonal feed lines. Axial ratio (AR) bandwidth is significantly enhanced because of inverted-L grounded strip with attached three straight strips. The 3-dB AR bandwidth of the antenna is about 60% in which return loss, and isolation are better than 10 and 15 dB, respectively.

110 citations


Journal ArticleDOI
TL;DR: In this paper, the authors presented a 28 GHz low insertion loss and compact size 4-bit phase shifter in 65 nm CMOS technology, which is composed of two types of passive phase shifters, high-pass/low-pass type and switched filter type.
Abstract: This letter presents a 28 GHz low insertion loss and compact size 4-bit phase shifter in 65 nm CMOS Technology. In order to get low insertion loss and compact size, this phase shifter is composed of two types of passive phase shifters, high-pass/low-pass type and switched filter type. Various techniques are used such as triple well body-floating, gate-floating, removal of capacitance of the off-state transistor using resonant inductor, and minimized interconnection line which is based on matching network. This phase shifter has 6.36 dB of average insertion loss over the 27.5–28.35 GHz, and loss variation is about 2 dB. The return loss is higher than 12 dB, RMS phase error is 8.98 $^{\circ}$ , OIP3 is 8.1 dBm at $-$ 10 dBm input power and its core size is 636 $\mu$ m $\times$ 360 $\mu$ m. To the authors' knowledge, these results are the state of the art in CMOS passive phase shifters in K-band frequency.

85 citations


Journal ArticleDOI
TL;DR: In this article, a dual-band reconfigurable terahertz patch antenna using a graphene-stack-defined backing cavity is presented, which employs patch resonance based on backing cavity defined by interleaved graphene/Al 2O3 stacks, which can be dynamically dual-resonance frequency-tuned on large range about 1 THz via electrostatic gating on the graphene stack.
Abstract: The concept of dual-band reconfigurable terahertz patch antenna using a graphene-stack-defined backing cavity is presented. The proposed antenna employs patch resonance based on backing cavity defined by interleaved graphene/Al 2O3 stacks, which can be dynamically dual-resonance frequency-tuned on large range about 1 THz via electrostatic gating on the graphene stack. The performance is analyzed in terms of its directivity, sidelobe suppression, return loss, and bandwidth for different chemical potential. By applying different voltages on graphene stack, the direction of the antenna main beam can be steered with appreciable variation range.

77 citations


Journal ArticleDOI
TL;DR: In this article, a compact wideband four-way filtering PD is presented, which includes a pair of looped coupled-line structures to provide the needed power division to four output ports.
Abstract: A compact wideband four-way filtering PD is presented. The structure of the proposed device includes a pair of looped coupled-line structures to provide the needed power division to four output ports. Moreover, a pair of short-ended coupled-line stubs is used to introduce multiple transmission poles and transmission zeros for a sharp cut-off of the passband and high upper-stopband rejection. A detailed design procedure is shown to determine the initial design parameters. A prototype is designed, simulated and measured experimentally. The measured results show 56.5% bandwidth centered at 1.5 GHz with more than 15 dB upper-stopband rejection up to 4.15 GHz, more than 13 dB in-band isolation, and 15 dB return loss at all output ports.

73 citations


Proceedings ArticleDOI
22 May 2016
TL;DR: In this article, the development, fabrication, and measurement of fully inkjet-printing 3D interconnects for wireless mm-wave packaging solutions is presented, where conductive silver nanoparticle and dielectric polymer-based inks are utilized to fabricate die attach, dielectrics ramp and CPW transmission line interconnect structures in order to interface a silicon die with a packaging substrate.
Abstract: This work outlines the development, fabrication, and measurement of fully inkjet-printed 3D interconnects for wireless mm-wave packaging solutions. Conductive silver nanoparticle and dielectric polymer-based inks are utilized to fabricate die attach, dielectric ramp, and CPW transmission line interconnect structures in order to interface a silicon die with a packaging substrate. Insertion and return loss are measured and compared with simulations over the range of 0–40 GHz. An inkjet-printed mm-wave bow-tie slot antenna is integrated with the IC die in order to highlight the highly versatile nature of this 3D interconnect technology for integration with emerging SoP technology.

66 citations


Journal ArticleDOI
TL;DR: In this article, a new class of wideband phase shifters on multimode resonator is proposed and developed, which have a simple structure, intrinsic wideband characteristic, large phase shift value, and easy adjustment in phase shift.
Abstract: In this paper, a new class of wideband phase shifters on multimode resonator is proposed and developed. Compared with its conventional counterparts, these new phase shifters have a few advantageous features such as simple structure, intrinsic wideband characteristic, large phase-shift value, and easy adjustment in phase shift. The phase properties of multimode resonator are at first studied to derive the quantitative relationship between the phase slope and their respective resonant frequencies. On the one hand, a prescribed wideband phase shift can be achieved by adjusting the impedance ratio $R_{z}$ of the multimode resonator and the electrical length of the reference line. On the other hand, the wide operating band can be intrinsically obtained over a frequency range covered by multiple resonant frequencies in the multimode resonator. In this context, the transmission-line models of the proposed phase shifters are deduced and synthesized to design these phase shifters with a prescribed phase shift value and return loss within the operating band. Moreover, the synthesized model can be directly mapped into all the physical dimensions, thus allowing for a quick design process. Finally, two 180° wideband phase shifters are designed, fabricated, and tested to verify the proposed design method and predicted frequency responses.

65 citations


Journal ArticleDOI
TL;DR: The capability of reconfigurable monopulse beams ensures that the proposed antenna is a good candidate for smart WAP applications.
Abstract: In this paper, a novel planar reconfigurable monopulse antenna with compact size is proposed and studied for indoor smart wireless access points (WAPs) application. Circular polarization is achieved by using a dual-mode substrate integrated waveguide (SIW) slot antenna. Two diagonal ports are individually used to excite the SIW element antenna to achieve a 180° phase-shifting excitation. A reconfigurable $2 \times 2$ prototype is developed with the proposed element antenna, and it uses eight PIN diodes as four switches to implement the reconfiguration. Sum beams, difference beams in azimuth and elevation planes, and bidifference beams are generated. Measurement results verify the designed prototype, showing that the antenna has a null depth of over 30 dB and a peak sum beam gain of 12.29 dBi. The measured 10-dB return loss bandwidths are 5.72–5.96, 5.75–5.95, 5.73–5.97, and 5.76–5.94 GHz for the sum, elevation difference, azimuth difference and bidifference beams, respectively. And their measured 3-dB axial ratio (AR) bandwidths are 5.84–5.88, 5.86–5.90, 5.85–5.9, 5.85–5.9, and 5.84–5.91 GHz. The capability of reconfigurable monopulse beams ensures that the proposed antenna is a good candidate for smart WAP applications.

63 citations


Proceedings ArticleDOI
01 Sep 2016
TL;DR: In this paper geometry of the antenna and various parameters such as return loss plot, gain plot, radiation pattern plot and VSWR plot are presented & discussed and they are in good match with simulated results.
Abstract: This paper presents a low profile microstrip patch antenna for next generation 5G devices. The proposed patch antenna has a compact structure of 20mm × 20mm × 1.6mm including the ground plane, which is suitable to be used in handheld devices. The antenna resonates at 10.15 GHz covering 5G frequency band. The proposed design provides a gain of 4.46dBi and the radiation pattern is omni-directional. In this paper geometry of the antenna and various parameters such as return loss plot, gain plot, radiation pattern plot and VSWR plot are presented & discussed. Measured results are also presented and they are in good match with simulated results.

58 citations


Journal ArticleDOI
TL;DR: In this paper, an in-phase power divider with a wide tuning range for the power division ratio across one octave bandwidth is presented, which uses a quarter-wavelength three-line coupled structure with controllable coupling factors using two centrally connected varactors.
Abstract: An in-phase power divider (PD) with a wide tuning range for the power division ratio across one octave bandwidth is presented. The device uses a quarter-wavelength three-line coupled structure with controllable coupling factors using two centrally connected varactors. One terminal of the central coupled line is connected to the input port, whereas its other terminal is grounded. The two coupled side lines are connected to the output ports, whereas an isolation resistor connects their other ends. The mode theory is used to analyze the performance and predict the initial dimensions. To validate the design, a prototype of dimensions 30 $\times$ 20 is built on Rogers RO6010 substrate and tested. The results indicate a tunable power division ratio from 1:1 to 1:2.4 with less than 0.5 dB additional insertion loss across the frequency band 0.7–1.4 GHz. The device has more than 10 dB return loss at all the ports and more than 15 dB isolation between the output ports. The two output signals are in-phase across the whole band with less than 8 $^{\circ}$ differential phase imbalance.

Journal ArticleDOI
TL;DR: In this paper, a fishnet based metamaterial (MTM) loaded rectangular microstrip patch antenna (RMPA) was proposed for THz applications and the negative refractive index of the MTM was displayed at frequency range between 1.05 and 1.1 THz.
Abstract: A fishnet based metamaterial (MTM) loaded rectangular microstrip patch antenna (RMPA) is proposed for THz applications. The negative refractive index of the MTM has been displayed at frequency range between 1.05 and 1.1 THz. This MTM can be used for improving the return loss, gain and radiation efficiency of RMPA. The return loss (S11), and gain are found as −57 and 3.57 dB, respectively. In addition, the bandwidth of −10 dB has been found as 8.2 %.

Journal ArticleDOI
TL;DR: In this article, a class of slow-wave substrate integrated waveguide (SIW) structures patterned with microstrip polyline is presented, theoretically studied, and experimentally validated, which demonstrates some interesting slowwave propagation effects.
Abstract: A class of slow-wave substrate integrated waveguide (SIW) structures patterned with microstrip polyline is presented, theoretically studied, and experimentally validated, which demonstrates some interesting slow-wave propagation effects. The slow-wave SIW (SW-SIW) enables the size reduction of a physically large circuit without sacrificing its performance. A size reduction of 40% of the lateral dimension is achieved with reference to that of the conventional SIW counterpart at the same cutoff frequency. Meanwhile, the phase velocity of the waveguide is also reduced by 40%, resulting in a smaller longitudinal dimension for a given electrical length. Both lateral and longitudinal effects give rise to a total size reduction, largely extending the operation range of SIW structures in the low-frequency region, which has often been restrained by a physical dimension-related cutoff frequency. Also, a transmission line-based two-dimensional (2-D) equivalent-circuit model is proposed and deployed for the modeling and analysis of the slow-wave mechanism. The results from the equivalent-circuit model agrees very well with that from the full-wave simulations. Furthermore, a broadband microstrip to SW-SIW taper with good return loss is designed for measurement verification. Using the proposed SW-SIW structure, the size of conventional SIW-based microwave circuits such as power splitters, couplers, and filters can be further reduced in addition to the existing size-reduction techniques.

Journal ArticleDOI
TL;DR: In this article, a transition from substrate integrated suspended line (SISL) to conductor backed coplanar waveguide (CBCPW) is proposed, which eliminates the drawbacks of the traditional suspended circuits and integrates the suspended circuits effectively.
Abstract: A novel transition from substrate integrated suspended line (SISL) to conductor backed coplanar waveguide (CBCPW) is proposed in this letter. The proposed transition utilizing the standard PCB techniques eliminates the drawbacks of the traditional suspended circuits and integrates the suspended circuits effectively. The new transition is a self-packaged system verified by both simulation and experiment results. Back-to-back transition structure has insertion loss of less than 0.6 dB and return loss of better than 15 dB from dc to 8 GHz.

Journal ArticleDOI
TL;DR: In this article, a phase shifter using MEMS-reconfigurable surfaces to individually block/unblock the E-plane stubs from the micromachined waveguide is presented.
Abstract: This paper presents a submillimeter-wave 500–550-GHz MEMS-reconfigurable phase shifter, which is based on loading a micromachined rectangular waveguide with 9 E-plane stubs. The phase shifter uses MEMS-reconfigurable surfaces to individually block/unblock the E-plane stubs from the micromachined waveguide. Each MEMS-reconfigurable surface is designed so that in the nonblocking state, it allows the electromagnetic wave to pass freely through it into the stub, while in the blocking state, it serves as the roof of the main waveguide and blocks the wave propagation into the stub. The phase-shifter design comprises three micromachined chips that are mounted in the H-plane cuts of the rectangular waveguide. Experimental results of the first device prototypes show that the microelectromechanical system (MEMS)-reconfigurable phase shifter has a linear phase shift of 20 $\mathbf {^{\circ }}$ in ten discrete steps (3.3 bits). The measured insertion loss is better than 3 dB, of which only 0.5–1.5 dB is attributed to the MEMS surfaces and switched stubs, and the measured return loss is better than 15 dB in the design frequency band of 500–550 GHz. It is also shown that the major part of the insertion loss is attributed to misalignment and assembly uncertainties of the micromachined chips and the waveguide flanges, shown by simulations and reproducibility measurements. The MEMS-reconfigurable phase shifter is also operated in an analog tuning mode for high phase resolution. Furthermore, a detailed study has been carried out identifying the reason for the discrepancy between the simulated (90 $\mathbf {^{\circ }}$ ) and the measured (20 $\mathbf {^{\circ }}$ ) phase shift. Comb-drive actuators with spring constant variations between 2.13 and 8.71 N/m are used in the phase shifter design. An actuation voltage of 21.94 V with a reproducibility better than $\mathbf {\sigma }=$ 0.0503 V is measured for the actuator design with a spring constant of 2.13 N/m. Reliability measurement on this actuator was performed in an uncontrolled laboratory environment and showed no deterioration in the functioning of the actuator observed over one hundred million cycles.

Journal ArticleDOI
TL;DR: A novel design of tapered dipole nanoantenna is introduced and numerically analyzed for energy harvesting applications where the antenna impedance, return loss, harvesting efficiency and field confinement are calculated using 3D finite element frequency domain method.
Abstract: In this paper, a novel design of tapered dipole nanoantenna is introduced and numerically analyzed for energy harvesting applications. The proposed design consists of three steps tapered dipole nanoantenna with rectangular shape. Full systematic analysis is carried out where the antenna impedance, return loss, harvesting efficiency and field confinement are calculated using 3D finite element frequency domain method (3D-FEFD). The structure geometrical parameters are optimized using particle swarm algorithm (PSO) to improve the harvesting efficiency and reduce the return loss at wavelength of 500 nm. A harvesting efficiency of 55.3% is achieved which is higher than that of conventional dipole counterpart by 29%. This enhancement is attributed to the high field confinement in the dipole gap as a result of multiple tips created in the nanoantenna design. Furthermore, the antenna input impedance is tuned to match a wide range of fabricated diode based upon the multi-resonance characteristic of the proposed structure.

Journal ArticleDOI
TL;DR: In this paper, a microstrip Rotman lens is used to feed a wide bandwidth series-fed microstrip patch antenna array, which has five beam ports, five array ports, four dummy ports and a footprint as small as 11 mm $\times10.7$ mm at 60 GHz operation frequency.
Abstract: This paper presents a new design technique and analysis for a microstrip Rotman lens which is feeding a wide bandwidth series-fed microstrip patch antenna array. In the proposed Rotman lens method, the length of the transmission lines does not affect the progressive phase delay. This reduces the complexity of the design and improves the performance parameters. An antenna array is utilized using open ended $\lambda /4$ stubs to support high gain, directivity, and a wide bandwidth. The Rotman lens and antenna arrays are fabricated on the top layer of a multilayer low temperature cofired ceramic substrate. The Rotman lens has been designed based on the presented technique, which has five beam ports, five array ports, four dummy ports, and a footprint as small as 11 mm $\times10.7$ mm at 60 GHz operation frequency. The implemented lens and antenna array exhibits good insertion loss, return loss, and wide bandwidth and shows phase error as small as 0.45° in the worst case scenario.

Journal ArticleDOI
TL;DR: In this article, a half-mode substrate integrated cavity bandpass filter with both continuous center frequency and 3 dB bandwidth tuning capabilities is presented, which adopts a superposed two-layer PCB with lumped varactors loading the central resonator to tune the center frequency.
Abstract: This letter presents a half-mode substrate integrated cavity bandpass filter with both continuous center frequency and 3 dB bandwidth tuning capabilities. The filter adopts a superposed two layers PCB with lumped varactors loading the central resonator to tune the center frequency. The first-invented semicircular metal sheet on the center rod not only reduces the filter size given a certain resonant frequency significantly by increasing the capacitance between the semicircular metal and the upper ground metal but also facilitates fine frequency tuning by using appropriate varactor $C_{\mathrm{tune}}$ . Surface mount varactors between two resonators change the inter-resonator coupling to adjust the 3 dB BW. Another varactor on the feed line can be used to adjust the external coupling. This filter demonstrates a BW range of 75–130 MHz around 1.5 GHz, a 3 dB BW range of 46–130 MHz around 1.3 GHz and a 3 dB BW range of 55–90 MHz around 1.11 GHz with 10 dB minimum return loss. Insertion loss ranging from 2.262 dB to 7 dB have been obtained.

Journal ArticleDOI
Abed Pour Sohrab1, Yi Huang1, Muaad Hussein1, Muayad Kod1, Paul Carter 
TL;DR: In this article, the effect of liquid on the performance of a UHF RFID tag is investigated, and it is found that the presence of the liquid increases the loss resistance in the equivalent circuit of the antenna.
Abstract: The effect of liquid on the performance of a UHF RFID tag is investigated in this letter. It is found that the presence of the liquid increases the loss resistance in the equivalent circuit of the antenna. This leads to impedance mismatching with a narrower bandwidth and degraded return loss. The proposed solution for compensating this effect is to add a resonant $RLC$ circuit with smaller resistance in parallel to the antenna body. This resistance corrects the increased loss resistance when the resonant frequency of the added part is close to the working frequency of the tag. The simulation and measurement results confirm an improvement in impedance matching that leads to the increase of the reading range.

Proceedings ArticleDOI
05 May 2016
TL;DR: A wideband and efficient rectenna suitable for 2.4 GHz-band RF energy harvesting from wireless LAN/Wi-Fi or similar devices and exhibits a high efficiency in the band of 2.41~2.47 GHz.
Abstract: This paper presents a wideband and efficient rectenna suitable for 2.4 GHz-band RF energy harvesting from wireless LAN/Wi-Fi or similar devices. We design a stacked patch antenna consisted of a driven patch and four parasitic patches. The proposed antenna performs well both in return loss and gain in the frequency band of 2.41∼2.47 GHz which almost covers all channels of 2.4GHz-band wireless LAN. In the band of 2.41∼2.47 GHz, the simulated return loss of proposed antenna is below −10 dB and the simulated gain is over 5 dBi. Furthermore, we design a rectifying circuit which also exhibits a high efficiency in the band of 2.41∼2.47 GHz with the power level as low as −20 dBm. Especially, at 2.472 GHz, the measured efficiency of rectifier is 4.3%, 24.3%, 48.5%, 63% for different input powers of −30, −20, −10, 0 dBm, respectively.

Journal ArticleDOI
TL;DR: The software simulated results are shows that the proposed antenna array provides good performance in terms of return loss, VSWR and Gain.

Journal ArticleDOI
TL;DR: In this article, a varactor-based filtering power divider was proposed for reconfigurable operating frequency and bandwidth with high in-band isolation, which achieved good impedance matching and isolation for all tunable states.
Abstract: This letter proposes a varactor-based filtering power divider that allows for reconfigurable operating frequency and bandwidth with high in-band isolation. A simple but effective tuning scheme was used to attain good impedance matching and isolation for all tunable states. Experimental results show that, for input return loss $>$ 16.6 dB, the center frequency and 1 dB constant absolute bandwidth can be tuned from 1.3 to 2.08 GHz and from 70 to 130 MHz, respectively. Moreover, this work demonstrates $>$ 26 dB output isolation, $ 0.23 dB magnitude imbalance, and $ phase imbalance. Measured and simulated results are in good agreement.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a new microstrip-fed printed slot antenna for use in dual-band wireless applications, which is in the form of Cantor square fractal geometry of the second iteration.
Abstract: Fractal geometries are attractive for antenna designers seeking antennas with compact size and multiband resonant behavior. This paper presents the design of a new microstrip-fed printed slot antenna for use in dual-band wireless applications. The slot structure of the proposed antenna is in the form of Cantor square fractal geometry of the second iteration. The slot structure has been etched on the ground plane of a substrate with relative permittivity of 4.4 and 1.6 mm in thickness. A parametric study is conducted to explore the effects of some geometrical parameters on the antenna performance. Results show that the antenna possesses a dual-band behavior with a wide range of resonant frequency ratio. In addition to the ease of fabrication and simple design procedure, the antenna offers desirable radiation characteristics. A prototype of the proposed antenna has been simulated, fabricated, and measured. The measured 10 dB return loss bandwidths for the lower and the upper resonant bands are 42% (2.35–3.61 GHz) and 20% (5.15–6.25 GHz), respectively. This makes the proposed antenna suitable to cover a number of operating bands of wireless systems (2.4 GHz-Bluetooth, 2.4 GHz ISM, 2.4/5.8 GHz-WLAN, 3.5 GHz-WiMAX, and 5.8 GHz-ITS).

Journal ArticleDOI
TL;DR: In this paper, a differential capacitive power sensor based on the seesaw-type microelectromechanical systems (MEMS) membrane is proposed, where the center part of the membrane is pulled down toward to the substrate, while the end parts are turned away from the substrate.
Abstract: In this letter, a differential capacitive power sensor is proposed based on the seesaw-type microelectromechanical systems (MEMS) membrane. When the microwave power is applied, the center part of the membrane is pulled down toward to the substrate. Meanwhile, the end parts are turned away from the substrate, because two anchors act like pivots. Hence, the capacitance between the center part and the electrodes increases, while the capacitance induced by the end parts decreases. This device is based on the MEMS technology and fabricated by GaAs monolithic microwave integrated circuit (MMIC) process. The tested return loss is about −29 dB at 1 GHz, −18 dB at 5 GHz, and −13 dB at 10 GHz. The insertion loss is better than 1.5 dB over 1–10 GHz. For the incident power from 1 to 100 mW, the measured capacitance change magnitude $\Delta C_{\mathrm {in}}$ increases from 0.1 to 7fF, while the capacitance change $\Delta C_{\mathrm {out}}$ magnitude varies from 0.1 to about 3 fF. Therefore, the sensitivity of the proposed power sensor is improved and on the order of 0.1 fF/mW. [2016-0014]

Journal ArticleDOI
TL;DR: Measurements prove that the antenna array allows integration into a worktop with only a minor influence on its return loss and mutual coupling, guaranteeing a bandwidth of at least 1.078 GHz and a minimum isolation between antenna elements of 30 dB within the entire (5.15-5.85) GHz band.
Abstract: A high-performance, three-element substrate-integrated-waveguide (SIW) cavity-backed slot antenna array that covers the (5.15–5.85) GHz band is designed for integration inside or underneath the worktop of a desk, to set up a stable, high data-rate ultra-short-range $3 \times 3$ multiple-input multiple-output (MIMO) wireless communication link with a mobile user (MU) positioned on top of that worktop. The antenna topology and array geometry are carefully selected to maximally exploit the multiplexing capabilities of the ultra-short-range $3 \times 3$ MIMO channel over a wide bandwidth, yielding an increased channel capacity and/or reduced power consumption. In addition, special care was taken to guarantee a channel capacity that is less dependent on the relative orientation of the MU. Furthermore, the SIW implementation technology is combined with innovative antenna materials to guarantee a low-profile, low-cost, stable, and high-performance broadband array design that maintains its excellent performance after integration. A prototype of the antenna array was fabricated, integrated according to two different integration scenarios, and validated. Measurements prove that the antenna array allows integration into a worktop with only a minor influence on its return loss and mutual coupling, guaranteeing a bandwidth of at least 1.078 GHz and a minimum isolation between antenna elements of 30 dB within the entire (5.15–5.85) GHz band.

Journal ArticleDOI
TL;DR: In this paper, a multi-mode resonator (MMR) is proposed to generate four main resonant modes in the desired band, i.e. two odd modes and two even modes.
Abstract: A compact ultra-wideband (UWB) bandpass filter based on a novel multi-mode resonator (MMR) is proposed. The MMR consists of a pair of open-circuited stubs and three pairs of coupled-line sections, which can generate four main resonant modes in the desired band, i.e. two odd modes and two even modes. The measured results of a fabricated one show that its bandwidth can cover the UWB frequency range and it has a sharp skirt due to two transmission zeros near its passband. Return loss in the passband is better than −10 dB. Meanwhile, at least −40 dB suppression can be achieved from 11.86 to 15.13 GHz and −30 dB suppression from 12 to 16 GHz.

Journal ArticleDOI
TL;DR: In this paper, a novel microstrip wideband balun bandpass filter (BPF) is presented for development of a balanced dipole antenna with wide operating band and high frequency selectivity.
Abstract: A novel microstrip wideband balun bandpass filter (BPF) is presented for development of a balanced dipole antenna with wide operating band and high frequency selectivity. By utilising the standing-wave property of current distribution along a half-wavelength (λ/2) open-ended microstrip line, out-of-phase signals are ideally obtained at two output ports of a balun. Meanwhile, proper coupling topologies between the open-circuited λ/2 microstrip transmission line and the quadruple-mode resonators are selected to achieve a balun BPF with both characteristics of balanced performance and wideband filtering properties. A balun BPF operating at 1.65 GHz with 32% fractional bandwidth is at first designed. The derived results not only exhibit good performance with 0.49 dB amplitude imbalance and 7.2° phase imbalance, but also achieve high selectivity relying on two transmission zeros. Next, this balun BPF is integrated with a balanced dipole antenna with a flat shape towards wideband and high-selective radiation. Both simulated and measured results achieve higher than 10 dB return loss and 2.4 dBi radiation gain over a band of 1.4–1.9 GHz.

Journal ArticleDOI
TL;DR: A compact microstrip diplexer for 4G wireless communication systems is proposed in this article, which consists of two bandpass filters based on the triangular open loop asymmetric stepped impedance resonator in order to have a small size and simple structure.
Abstract: A compact microstrip diplexer for 4G wireless communication systems is proposed in this paper. This diplexer consists of two bandpass filters based on the triangular open loop asymmetric stepped impedance resonator in order to have a small size as well as simple structure. The T-shaped open stub is used for attenuating the undesired modes. Attenuation level for the proposed diplexer is less than 21 dB in the range of 0–10 GHz owing to using this T-shaped open stub. The center frequency of each filter can easily change in the range of 20 MHz through varying the gap length of the resonator without any changes in the whole structure of the diplexer. The result of this is the stability of other parameters like insertion loss, return loss and isolation. This diplexer has a narrow band frequency response that makes it suitable for modern wireless communication systems. Finally, the diplexer is fabricated at 2.30 and 2.55 GHz and measurements demonstrate a good agreement between simulated and fabricated diplexer.

Journal ArticleDOI
01 Jul 2016-Optik
TL;DR: In this article, a metamaterial layer is implemented to improve radiation characteristic of dipole antenna at THz domain, which is known as Fabry-Perot cavity, and the antenna gain is increased more than 120% and bandwidth is amended around 82%.

Journal ArticleDOI
TL;DR: In this article, a compact asymmetric coplanar strip (ACS)-fed printed monopole antenna for dual frequency operation is presented, which is composed of an ACS-fed monopole structure and two semi circle shaped radiating branches, which occupies a very small size of 13.4? 22.7 mm2 including the ground plane.
Abstract: In this paper, a compact asymmetric coplanar strip (ACS)-fed printed monopole antenna for dual frequency operation is presented. The proposed antenna is composed of an ACS-fed monopole structure and two semi circle shaped radiating branches, which occupies a very small size of 13.4 ? 22.7 mm2 including the ground plane. By properly selecting the length and position of these branches, two desired operating bands can be achieved and tuned independently. The simulated and measured return loss results shows that the proposed antenna can be used for long term evolution 2500 (2500---2690 MHz), WLAN 5.2 GHz (5.15---5.35 GHz)/5.8 GHz (5.725---5.825 GHz), WiMAX 5.5 GHz (5.28---5.85 GHz) and 4.9 GHz (4.94---4.99 GHz) public safety applications. The omnidirectional and bidirectional radiation pattern characteristics in H-plane and E-plane of the proposed antenna along with acceptable peak gain make the best suitable candidate for the above intended applications.