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A broadband microwave metamaterial absorber with wide-angle property is introduced in this paper. The bandwidth of effective absorption (over 90% absorptivity) of the proposed absorber is from 2.2 GHz to 18.4 GHz, covering almost the whole S-, C-, X-, and Ku-band, with relative absorption bandwidth of 157%. The total thickness of the proposed absorber is 15 mm, which corresponds to 0.11λ at the lowest operating frequency. To provide wide-angle and broadband frequency matching, a wide-angle impedance matching layer is used in the unit cell design. The proposed absorber can realize more than 80% absorptivity for TE polarization and more than 90% absorptivity for TM polarization from S-band to Ku-band when the incident angle is less than 50°. Equivalent circuit method is used to analyze the proposed absorber and the circuit model analysis results agree quite well with the numerical full-wave simulation.

This paper proposes high power microstrip non-Foster Class E GaN HEMT amplifier. The power amplifier (PA) was designed based on Cree CGHV40030FP GaN HEMT biased at drain supply voltage of 50 V and cut-off gate voltage of −3 V. Non-Foster circuit has been used in the input matching network to generate the negative capacitance required to cancel out the gate-source capacitance of the power transistor. The PA operates from 3.1 to 3.3 GHz at 3.2 GHz center frequency. The PA has 57.6% drain efficiency, 52.9% PAE, 42.5 dBm output power and 10.5 dB transducer power gain at 32 dBm input power.

An ultra-wideband and polarization-insensitive microwave absorber, which is composed of three layers of metasurfaces with different patterns and sheet resistances, is proposed in this paper. The bandwidth of effective absorptivity (over 90%) is from 6 GHz to 50 GHz, with relative absorption bandwidth of 157%. The equivalent circuit of the proposed absorber is investigated thoroughly. The circuit model analysis results agree quite well with the numerical simulation, which indicates the accuracy of the equivalent circuit model. The performances of this absorber under various polarizations and incident angles are also investigated. The results indicate the proposed absorber is polarization insensitive and has relatively good stability of wide incident angles.

In this paper, a printed graphene compact, low-cost, disposal, flexible and conformal, coplanar waveguide (cpw) fed, linear array antenna is proposed. It was designed for 5.8GHz radars, portable electronic devices, and commercial wireless LAN applications and manufactured by screen printing formulated highly conductive graphene ink on paper substrate. The array achieves 73% total radiation efficiency and a peak gain value of 4.5dBi at 5.8GHz, with its bandwidth ranges from 4.6GHz to 7.9GHz (52.8%). Over the operating frequency, the radiation of the antenna was proved as a typical radiation pattern of a patch antenna array.

This paper presents the design of a coplanar waveguide fed planar monopole antenna printed by graphene nanoflakes conductive ink. By using the band rejection slits, the compact monopole can excite 2.4/5 GHz frequency bands for WIFI (2.4-2.483 GHz and/or 5.150-5.825 GHz) and WLAN applications. The measured results show the antenna has the impedance bandwidths of 730 MHz (2.11-2.84 GHz) and 2430 MHz (4.20-6.63 GHz), which can cover the WLAN 2.4/5 GHz bands. The gain and radiation pattern results also verify effective radiations from the designed dual band antenna in far field.

The design and fabrication of a novel e-textile wideband UHF RFID tag antenna is presented. The proposed antenna is verified by simulation and measurements. The RFID tag read range is over 6.5 m in the frequency band between 860 and 960 MHz. The maximum read range is measured at 7.23 m in air and 4.71 m on body.

A novel methodology for designing and applying artificial magnetic conductor (AMC) through controlling pattern’s surface impedance instead of shape is proposed and analyzed. A wideband metamaterial radar absorber applying this methodology is designed and verified numerically. Simulation results indicate this methodology can be used to widen absorption bandwidth for metamaterial radar absorbers.

This paper proposed a novel printed graphene based monopole antenna for UWB communication applications. Screen printed graphene laminate with the conductivity of 4.1×104 S/m is used in this paper to replace expensive metal inks. The CPW feed planar monopole antenna has a wideband characteristic from 5 GHz to 13.5 GHz and omnidirectional radiation patterns. Simulated and measured results are compared and discussed in this paper.

This paper presents the design, fabrication and measurement of a planar inverted F-shaped monopole antenna printed by graphene nanoflakes conductive ink. With the use of simple inverted-F shaped monopole structure, 2.4/5 GHz bands are excited to be used in WiFi band WLAN applications.

A novel e-textile integrated wideband monopole antenna designed for body-worn energy harvesting systems is presented. The proposed antenna is constructed with silver coated conductive threads woven into cotton substrate, and the operation bandwidth of which covers GSM bands (range 870.4-915 MHz and 1.7-1.9 GHz), LTE bands (range 0.79–0.96 GHz; 1.71–2.17 GHz; and 2.5–2.69 GHz) and Wi-Fi frequencies (2.4 and 3.6 GHz).

in this paper, we present the design and characterization of two radar absorbers based on periodic structures. Near unity absorbance over a wideband frequency is achieved under normal, as well as oblique incidence of a linearly polarized (LP) electromagnetic (EM) planar waves. The reflected wave is measured for both transverse electric (TE) and transverse magnetic (TM) polarizations. The first absorber is a low profile monolayer periodic structure (height 90% in the range of [5.6 - 9.1] GHz. The second structure is an ultra-broadband thin FSS based radar absorber. An absorption rate above 89% is obtained in the frequency band of [4.8–11.1] GHz. The absorption remains very interesting for oblique incidences; up to 30°. The total height is < wavelength/7. The theoretical thickness to real thickness ratio (limit height of ROZANOV is as high as 80%. The experimental results are in good alignment with the numerical results. The experimental results are very promising and our designs can be used to tackle EM interferences for a large domain of applications.

This paper proposed a novel metamaterial inspired long read range UHF RFID tag antenna. A square split ring resonator is acting as a radiator, which operates under electric resonance mode rather than common magnetic resonance one. T-matching network was used to provide a good conjugate matching between UHF RFID chip and the radiator. The maximum read range is over 12 m (EIRP = 4 W). Simulated and measured results are compared and discussed.

This paper presents an MMIC (monolithic microwave integrated circuit) non-Foster circuit enabled Class-J GaAs pHEMT (Gallium Arsenide pseudomorphic high electron mobility transistor) power amplifier. The power amplifier was designed based on WIN Semiconductor PP10–10 process transistor biased with drain supply voltage of 2.5 V at quiescent drain-to-source current (I DSq ) of 2 mA. The power amplifier operates from 55 to 59 GHz with center frequency of 57 GHz. The non-Foster circuit forms part of the input matching network and provides the negative capacitance required to cancel the transistor input parasitic capacitance. The effective capacitance at 57 GHz stands at −0.16 pF. The proposed MMIC power amplifier has chip dimension of 3 × 1.8 mm, 53.9% drain efficiency, 34% power added efficiency (PAE), 14 dBm output power and transducer power gain of 4 dB at 57 GHz and 10 dBm input power.

This paper proposes Microstrip non-Foster circuit (NFC) enhanced high efficiency high power class-J GaN HEMT (gallium nitride high electron mobility transistor) amplifier. The NFC enhances the performance of the power amplifier (PA) by cancelling the power transistor's input parasitic capacitance. The PA was designed based on Cree's CGHV40030FP GaN HEMT biased with drain supply voltage of 50 V at quiescent drain-to-source current (I DSq ) of 15 mA. The NFC is part of the input matching network and contains two GaN HEMTs biased with drain supply voltage of 20 V at IDSq of 3 mA. The PA operates from 2.0 to 2.2 GHz. The NFC negative capacitance at 2.1GHz center frequency stood at −2.4 pF. The NFC PA has output power of 43.9 dBm (24.5 W), 69.3% drain efficiency, 66.4% power added efficiency (PAE) and transducer power gain of 11.9 dB.

This paper presents a design of transmission line based RF switch with graphene. The on-off states of the switch can be adjusted electrically due to the unique properties of monolayer graphene. The transmission between two ports varies more than 30dB when voltage changes from 0 to 30 V. The RF switch provides enough insertion loss and good isolation in on and off states.

Monolayer graphene microwave resonator and THz antenna are presented. CVD graphene is used for the microwave resonator fabrication and exfoliated graphene for he THz antennas. Raman spectroscopy has been adopted to confirm the layer number of graphene. The measurements were carried out for the resonator in the microwave spectrum, showing that graphene can work well as a resonating unit in the short-end resonating structure. The THz antenna has also been fabricated. The work presented here demonstrates that graphene can find its applications in developing graphene based devices at microwave and THz spectrums.

Design, fabrication and analysis of graphene based resonators at microwave frequencies are presented. Chemical Vapor Deposited (CVD) graphene is used to fabricate the resonating stub, where Raman spectroscopy has been adopted to confirm the layer number of graphene. The measurements were carried out from 12 GHz to 28 GHz. The results of graphene resonator's input impedance show that graphene could work well as a resonating unit in the short-end resonating structure, demonstrating that graphene based resonators can find a lot of applications in developing guided graphene based devices at microwave frequencies.

In this paper a new configuration for a flexible wide band CPW fed slot antenna is introduced. The proposed slot antenna was simulated on a flexible substrate has compact geometry area of 34 × 25 mm2 qualifies it to meet the integration requirements of small indoor receiver applications. The structure of the slot antenna was designed to achieve circular polarization over wide band. Moreover, the antenna has good far field radiation characteristics over the bandwidth. The design principals along with simulation results are presented in this work.

In this paper, a polarization diversity dielectric resonator antenna (DRA) is presented. In the proposed design, DRA is fed by using two narrow slots on the top wall of two adjacent substrate integrated waveguide structures, which shares a common row of metallic vias. The orientation of the slots are orthogonal to each other which generates two linear orthogonally polarized radiation pattern at same frequency to implement polarization diversity. The rectangular DRA is excited in higher order TE 113 mode in order to obtain a DRA with larger dimension at 10 GHz. The measured impedance bandwidth (S 11

A new and simple approach to design high selectivity microstrip bandpass filter (BPF) is reported. Based on the signal interference concept, the selectivity of a BPF using composite right/left handed transmission line (CRLH TL) unit cell is significantly improved. Thus, by employing a single coupled line section and CRLH TL unit cell in the feedback, a bandpass filter with high selectivity, multiple transmission zeros (TZs) within the upper stopband and low insertion loss can be realized. The simulation results show that the proposed BPF has a fractional bandwidth of 8% centred at 2.4 GHz with high roll-off rate of 300 dB/GHz.

This paper is composed of two parts. First, we explain the basic concepts of general composite right / left handed transmission line designs using ferrite medium. We explain its different analysis unlike conventional dielectric case. Hence, the ferrite left handed transmission line properties are emphasized compared to dielectric one. Second, we present some novel microwave device applications based on ferrite left handed transmission lines. The theories of these devices are based on the concepts introduced in the first part. These applications comprise quarter wavelength transformers and zeroth order resonator. Such applications have the advantages of compact size in addition to the tunability properties. Moreover, the proposed devices require small DC magnetic bias.

In this paper, we introduce a modified printed E antenna loaded with negative permittivity metamaterial structure. The proposed lading is suggested to decrease the physical size of the antenna compared to conventional printed E antenna operating at the same frequency. Moreover, the loading adds an extra resonance order which can result in sharp operating frequency with reasonable bandwidth. The antenna is designed for WiMAX service with centre frequency at 5.25 GHz and bandwidth of 200 MHz. Moreover, the antenna has very sharp selective properties to reject reception outside this band. The antenna size is only 30 × 30 mm2 which represents 64 % size reduction compared to conventional printed E antenna operating at the same frequency. The theoretical design concepts, full wave simulations and experimental measurements are introduced.

This paper presents the design of a super-compact dual-wideband bandpass filter (BPF) using quarter-wavelength slotted open-circuited stubs (SOSs). These slotted open stubs are used to define the second and the third stopbands at 3 and 9 GHz respectively. Both stubs are separated by quarter-wavelength impedance transformers. Unlike conventional quarter-wavelength impedance transformers, this filter has a high-pass meandered line that is shorted to ground to form an additional stopband at zero frequency. Using this approach, a dual-wideband bandpass filter is designed, fabricated and measured. The measured results show that the fabricated dual-wideband BPF has two passbands with a fractional bandwidth of 117% and 36%, at respective center frequencies of 1 GHz and 6.65 GHz. The filter has a compact size (0.09 λg × 0.05 λg) and exhibits an attenuation level greater than 20 dB up to 12 GHz.

This paper reports shielding effectiveness of screen printed graphene laminate for EMI applications. The graphene laminate was screen-printed on normal paper and cut to fit C band waveguide size (34.85 × 15.80 mm2) for measurement. The measurement results show that the average shielding effectiveness is above 32 dB across the whole C band, indicating that screen printed graphene laminate can be a viable alternative to printed metal to provide desired reflection loss.

This paper presents design of compact tunable dual band asymmetric coplanar strip -fed monopole antenna based on graphene sheet. The proposed antenna is consisted of ACS-fed folded monopole antenna with inverted two L branches which achieve very compact size. The proposed antenna is operated at 2.4 GHz and 5.8 GHz which is used for wireless applications. The graphene sheet is used to achieve the desired tunability. The resonance frequency of the antenna can be electrically tuned by applying DC voltage to the graphene sheet which changes chemical potential of this sheet. The Details of the antenna design and simulation results are presented and discussed. The proposed antenna shows nearly omnidirectional radiation characteristics.

A cross-coupled differential VCO with low phase noise variation is presented. The VCO core adopts a metal-oxide-metal (MOM) digital switching capacitor array (DSCA), which is connected in series and in parallel to the nMOS varactor in order to reduce the KVCO variation. For further gain linearity, wider tuning range and minor phase noise variations, this varactor bank is connected in parallel to three nMOS varactor pairs. Each pair is biased at a different voltage. The proposed VCO has been designed and implemented in UMC 130-nm, 6-metal CMOS technology and operates from 3.45 GHz to 6.23 GHz with 55.6% tuning range, phase noise variations ranging between −134 dBc/Hz and −130.8 dBc/Hz and power consumption below 6 mW at supply voltage of 3.2 V. The simulated phase noise at 1 MHz offset is 132.4 dBc/Hz at 5.0 GHz and a good FOM performance of approximately 204.5 dBc/Hz is achieved.

A low-profile top loaded folded monopole antenna with wide band omnidirectional radiation patterns is presented in this letter. The antenna is designed using a short vertical monopole element placed on a metallic reflector plane (MRP). The antenna impedance bandwidth is enlarged by adding vertical shorting pins at appropriate locations between the loading circuit and the MRP. The proposed antenna was studied numerically in the VHF frequency range. To meet with our measurement facilities, the antenna prototype was realized and fully characterized around 2.1 GHz. The experimental results are in good agreement with the numerical simulations. The antenna radiation patterns are omnidirectional with high radiation efficiency (> 90%) in a relatively large frequency band (11.5% bandwidth).

This paper presents the design of a reconfigurable antenna design using graphene based switch, where its working frequencies can be adjusted by switching between on/off states. The switching comes from the varying conductivity of graphene biased by external voltage. The working frequency moves from 838 MHz to 1.588 GHz when voltage is applied to change chemical potential in the range from 0 to 0.8eV. The promising results provide an alternative using graphene in frequency reconfigurable antennas.

A novel resistorless digital capacitor switching array (DCSA) has been implemented into a wideband CMOS VCO for 5-GHz WiMAX/WLAN applications. The proposed DCSA is added both in series and parallel to nMOS varactors. Based on this, a wideband VCO is achieved, which not only exhibits lower phase noise in comparison with reported state-of the-art wideband VCOs, but also has low phase noise variation of less than 5 dBc/Hz. In addition, it has demonstrated low power consumption, improved linearity of the f-V curve and extended tuning range. The proposed VCO has been designed using UMC 130 nm CMOS technology. It operates from 3.65 GHz to 6.34 GHz, with a phase noise of −132.70 dBc/Hz at 1 MHz offset, a figure of merit (FoM) of −202.9 dBc/Hz, less than −41 dBm spurious harmonics and total VCO core power consumption of 2.88 mW from a 3.2 V supply voltage.

0.1 μm gate length GaAs pHEMT having gate peripheries of 2×25 μm (number of gate finger × unit gate width) is fabricated on the 2mil (50.8 μm) GaAs/AlGaAs/InGaAs substrate using PP10-10 process. This work presents a measurement based bias dependent model for a 2×25 μm GaAs pHEMT. Measurement includes pulsed I-V and on wafer scattering parameters for the frequency range of 45 MHz to 110 GHz. Comparison of measurement data and WIN foundry's process design kit (PDK) model is presented using Advanced Design System (ADS).

This paper presents the design of a reconfigurable planar antenna design using graphene based switch, where its working frequencies can be adjusted by applying different voltages to connect or disconnect four patch sections to a midsection of the planar antenna. The switching comes from the varying chemical potential in the range from 0 to 0.8eV of graphene biased by external voltage. The promising results provide an alternative using graphene in frequency reconfigurable antennas.

In this paper, we present the concept and design of beam scanning terahertz antenna based on graphene arrays. The main lobe direction is verified to be scannable with flexibility introduced by graphene. The working principle of the beam scanning is further studied based on secondary reflection theory. This work can be further extended to flexible metasurface/coding metamaterial based antennas with graphene.

In this paper, a new via-less ultra-wideband (UWB) bandpass filter design based on a composite right/left-handed transmission line (CRLH-TL) unit cell is presented. Microstrip capacitive patch is used to provide virtual ground and replace the via in the conventional CRLH TL. Via fabrication complexity can be avoided for large-scale and cost-effective production by using microstrip patch. By cascading the interdigital coupled line with a low-pass filter (LPF) based on symmetrical split ring resonator (SSRR) defected ground structure (DGS), an UWB frequency response is achieved. SSRR DGS was used to obtain wider upper-stopband and sharp roll-off rate. The filter has compact size (15.6 × 13 mm2) and exhibits a rejection level greater than 20 dB at both upper and lower stopband. The filter has an insertion loss of 0.9 dB, a return loss better than 14 dB, and a fractional bandwidth of more than 100% at center frequency of 6.8 GHz.

This paper presents a novel compact planar dual-band spurious-free antenna based on metamaterial stepped-impedance resonators. The antenna provides the capability of controlling both of the frequency bands, while ensuring an extended spurious-free stopband. The antenna is designed to operate at UMTS and WLAN frequencies of 2.1 GHz and 2.4 GHz, respectively. The antenna dimensions are only 2 × 2 cm2, which is 50%smaller compared to a conventional half-wavelength patch antenna operating at the same frequencies. Operation mechanism of this antenna will be addressed elsewhere but this paper serves as proof of concept as it illustrates that simulation and measurement results are in close agreement; hence confirming the feasibility of this simple yet efficient antenna.

A novel Bull's eye ultra wideband THz antenna consists of circular slit surrounded by corrugated periodic grooves is reported. The antenna has been analyzed numerically. The simulation results show that the antenna has an impedance bandwidth of 630%, ranging from 57GHz to 400GHz. The antenna is modeled as perfect electrical conductor (PEC) with identical width and length of 34mm and compact thickness of 1.2mm. The antenna has a high gain performance over the operation bandwidth as it achieves gain of 21.5 dB at 400GHz.

This work presents an ultralow phase-noise and wide turning-range voltage-controlled oscillator (VCO) for 5.72GHz WiMAX applications. The fully integrated VCO is designed and simulated using 130-nm CMOS technology. Instead of using the conventional diode-based varactor in the tank design, high-performance body-grounded NMOS transistors are employed as effective varactors. A controlled self-biasing current source is implemented to avoid higher power supply sensitivity and higher up-conversion of flicker noise. The proposed VCO-measured results demonstrate a worst case phase noise of -132.68dBc/Hz at 1MHz frequency offset with an excellent figure of merit (FOM), which is -201.6dBc/Hz under a power consumption of 2.21mW. The VCO shows a tuning range of approximately 37.59%.

This paper presents a compact triple band metamaterial antenna for different wireless applications. The designed antenna is based on a new configuration as half mode metamaterial left handed transmission line. The proposed antenna was designed to cover the frequency bands from 2-2.4 GHz, 5.4-6 GHz, and 6.8-8 GHz. The theoretical design principles of half mode left handed transmission line antenna is explained. The antenna design has been validated using the electromagnetic full wave analysis. The antenna has the advantages of a compact size (only 2.5 × 2.5 cm2) which is only is less than 25% at lower frequency band compared to the size of the conventional patch antenna. The results confirm the antenna triple bands operation with return loss better than 15 dB at each operating band and better than 10 dB cross polarization isolation.

In this article is presented a new left handed metamaterial structure, full built on the top layer of a microstrip transmission line. The LH-TL proposed is constructed loading a common Microstrip-TL with CSRR's to produce a negative permeability, while adding capacitive couplings to produce a negative permeability along the transmission path, allowing the propagation of signals with anti-parallel group and phase velocities. Thus the structure proposed keeps all the electromagnetic advantages of a left handed metamaterial without any structural difference to the common microstirip transmission line. The main advantage of the left handed transmission line proposed, (compared to currently reported left hand transmission lines), is that this new metamaterial transmission line avoid the interaction of the bottom layer or any other quasi lumped structure to create the left hand effect. Consequently, undesired couplings are avoided and parasitic effects are reduced opening new possibilities in the design of passive structures. The results presented, are obtained from 3-D EM simulations showing a clear left hand transmission of signals in the range between 1.7 GHz and 2.3GHz. This contribution presents the first results reported in literature regarding to the construction of a left hand transmission line using only one metal layer.

This paper presents a novel Figure of Merit (FOM), low-phase-noise, LC-tank voltage-controlled oscillator (VCO). The work presents a fully integrated 6.72GHz VCO designed and simulated using 130-nm CMOS technology. Instead of using the conventional diode-based varactor in the tank design, a high-performance metal-oxide-metal (MOM) capacitor is employed as an effective varactor. The proposed VCO-measured results demonstrate a worst case phase noise of - 124.13dBc/Hz at 1MHz frequency, offset from a 6.72GHz carrier. An optimization technique is used to design an excellent FOM, which is -193.02dBc/Hz under a power consumption of 2.3mW. The VCO shows a tuning range of approximately 14%. To the best of our knowledge, this VCO presents the highest FOM level and the lowest phase noise compared to prior state-of-the-art solutions for the same frequency range.

This paper presents a compact dual band metamaterial antenna for WiMAX applications. The reported antenna was based on using a metamaterial modified left handed transmission line unit cell. The designed antenna was introduced to operate with the WiMAX lower 2.4 GHz band and upper 5.8 GHz band. The designed antenna has the advantages of its compact size (only 2 × 3) cm2. Compared to the conventional patch length, the designed patch radiator is only 25% at 2.4 GHz and 60% 5.8 GHz. The antenna designed was discussed theoretically and its performance was verified using the electromagnetic full wave simulations. The results confirm that the antenna can introduce the dual bands operation with return loss better than 15 dB at each operating band. Moreover, the radiation pattern is almost omnidirectional at the two bands.

Plasmonic antenna is capable of replacing an array antenna producing directive high gain beam at a desired direction by structuring the metal surface with certain patterns, having characteristic dimensions on a scale much smaller than the wavelength of the microwave. Excitation of localized surface plasmon modes on structured metal surface strongly localized the microwave. This enables the metal surface to confine, guide and manipulate the microwave in an open structure through sub-wavelength apertures to produce the directive beam radiation. This paper presents the ability of a structured metal surface to manipulate microwave propagation in an open structure and to support high gain radiation of 17 dB through a sub-wavelength aperture. The CST Microwave Studio (CSTMWS) simulation tool is used to simulate and analyze the designed plasmonic antenna performance.