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The authors present a novel wideband two‐dimensional voltage‐controlled attenuator (VCA). The proposed design employs both stacked‐FET configuration and distributed structure to achieve wideband performance, high power, and high dynamic range simultaneously. A systematic design methodology is also illustrated along with a fabricated prototype to verify the concept. The chip fabricated in a 0.15‐μm Gallium Arsenide (GaAs) process exhibiting a measured power at 1‐dB compression (P1dB) of 25.5 dBm with a corresponding dynamic range of 32 dB. The insertion loss ranges from 2 to 5 dB over the bandwidth from 2 to 40 GHz. Furthermore, the chip is not only very compact (0.84 mm2), but it also requires only a single positive supply voltage, which makes it more appealing to highly integrated wireless applications.

This letter presents a linear wideband differential optical driver amplifier in a 90-nm silicon germanium (SiGe) bipolar-complementary-metal-oxide-semiconductor (BiCMOS) process. The amplifier utilizes a modified triple-stacked heterojunction bipolar transistor (HBT) topology with emitter degeneration to achieve high output voltage swing and high linearity. The amplifier achieves 13.2-dB voltage gain with a bandwidth from dc to 53 GHz. The amplifier can deliver a 4-V peak-to-peak differential ( $V_{\mathrm {ppd}}$ ) with a total harmonic distortion (THD) of 1.6% at 1 GHz. The amplifier consumes 630-mW dc power at the small-signal operation.

A wideband monolithic microwave/millimeter-wave integrated circuit (MMIC) distributed amplifier (DA) using a 3-D interdigital capacitor at the input of the gain cell is demonstrated in an indium phosphide (InP) heterojunction bipolar transistor (HBT) process. The proposed DA using interdigital capacitors improves the input return loss at high frequencies compared with the one implemented with conventional metal–insulator–metal (MIM) capacitors. The fabricated amplifier achieves a measured average gain of 10.5 dB over a 3-dB bandwidth from 1 to 160 GHz. The maximum measured saturated power ( $P_{\mathrm {sat}}$ ) is 17.8 dBm with the corresponding 1-dB compression power ( $P_{\mathrm {1\,dB}}$ ) of 15 dBm at 55 GHz. The amplifier achieves a minimum $P_{\mathrm {sat}}$ of 14.6 dBm up to 110 GHz.

This paper presents the design and development of miniature coils for wireless power and data transfer through metal. Our coil has a total size of 15 mm × 13 mm × 6 mm. Experimental results demonstrate that we can harvest 440 mW through a 1 mm-thick aluminum plate. Aluminum and stainless-steel barriers of different thicknesses were used to characterize coil performance. Using a pair of the designed coils, we have developed a through-metal communication system to successfully transfer data through a 1 mm-thick aluminum plate. A maximum data rate of 100 bps was achieved using only harvested power. To the best of our knowledge, this is the first report that demonstrates power and data transfer through aluminum using miniature coils.

This letter demonstrates the application of the second-harmonic injection linearization technique in a field-effect transistor (FET) resistive mixer operating at $Ka$ -band. The single-ended mixer uses a 0.15- $\mu \text{m}$ gallium arsenide (GaAs) pseudomorphic high electron-mobility transistor (pHEMT) at its core. Compared to the same mixer without the second-harmonic injection, the linearized mixer achieves an improvement of up to 8 dB in the third-order intermodulation (IM3) levels while leaving the fundamental output power and noise figure unaffected. To the best of authors’ knowledge, this is the first demonstration of the technique with a mixer operating at millimeter-wave frequencies.

In this paper, we present the design and development of ultra-small coils for through metal power transfer applications. Our coil has a total size of 15xl5x2 mm. We determined the optimal wire gauge for the coil to be 24AWG and optimal frequency of 2 kHz. Our experimental results demonstrate that we can harvest 100 mW power through 1 mm thick aluminum using our proposed coils. To the best of our knowledge, this is the first report of ultra-small coils for through metal power transfer.

A high output power monolithic microwave/millimeter-wave integrated circuit (MMIC) distributed amplifier (DA) is demonstrated in an Indium Phosphide (InP) hetero-junction bipolar transistor (HBT) process. The DA employs nine double-stacked HBT gain unit cells with the proposed parallel/series metal-insulator-metal (MIM) configuration for the input coupling capacitors. The fabricated amplifier achieves a measured average gain of 11.5 dB over a 3 dB bandwidth from 1 to 150 GHz with a noise Figure (NF) of 10.3 dB. The maximum measured saturated power $(P_{sat})$ is 18.3 dBm with the corresponded 1-dB gain compression power $(P_{1dB})$ of 15.4 dBm at 50 GHz. The power-added-efficiency (PAE) of the amplifier is 10 % at 100 GHz.

This paper presents the design and development of an integrated wireless power transfer and data communication system. The power and data transfer share a common inductive link that consists of two identical Helical coils placed on both sides of a carbon composite barrier. Power and data are transferred simultaneously through a 5-mm thick carbon composite barrier without any physical penetration or contact. Power transfer measurements show that the system can deliver 9.7 AC power to the receiving coil with a power transfer efficiency of 36% through the carbon composite barrier. The system achieves a bidirectional half-duplex data communication with the data rate of unit 1.2kbit/s.

A two-stage Ka-band Doherty power amplifier (DPA) using a stacked field-effect transistor (FET) cell is presented. We demonstrate, for the first time, the two critical parameters in a stacked-FET topology that must be designed specifically for a Doherty operation: the gate capacitance and the bias voltage of the stacked transistor. The two parameters strongly determine the DPA output power, power-added efficiency (PAE), and power gain flatness. Furthermore, we also demonstrate a dual-driver topology to boost the amplifier gain without scarifying PAE, and a proposed bias circuitry to deal with the high gate leakage current of an enhancement mode (E-mode) process. The stacked-FET DPA prototype is fabricated in an E-mode 0.15- $\mu \text{m}$ gallium arsenide (GaAs) process to verify the concept. At 28 GHz, the 2.9 mm $\times1.7$ mm integrated chip exhibits a measured gain of 14.4 dB, an output power of 28.7 dBm, with an associated 37% peak PAE and 27% PAE at 6-dB power back-off. To the best of the authors’ knowledge, the DPA achieves among the highest gain and highest power density of all reported DPAs at millimeter-wave frequencies.

© 2017 IEEE. We present the development of a low-loss, high-power, and ferriteless balun that operates over 0.1-1.6 GHz bandwidth. The proposed balun employs a novel compensated circuit, a single quarter-wave semirigid coaxial cable and an on-board inductor on a thermoset ceramic board to achieve high power and ultrawide bandwidth performance. The experimental results show that the balun achieves a measured average insertion loss of less than 0.5 dB and return loss of better than 10 dB from 100 MHz to more than 1.6 GHz. Within the measured bandwidth, the amplitude and phase imbalances are within ±1 dB and ±5°, respectively. Multiphysics analysis and high-power measurements demonstrate that the balun can handle more than 600 W and above at 1.6 GHz. To the best of our knowledge, the reported balun has the highest measured power handling capability per the largest 16:1 bandwidth ratio to date.

We present the design and development of a Ka-band Doherty power amplifier (DPA) that achieves high efficiency at power backoff (PBO) using a new load modulation scheme and a proposed load–pull-based design technique. Using the proposed technique, the device size of the peaking amplifier and the impedance of the quarter-wavelength ( $\lambda $ /4) inverter are properly chosen to achieve high power-added efficiency (PAE) at a specific PBO level. The DPA is fabricated in a 0.15- $\mu {\text{m}}$ gallium arsenide pseudomorphic high-electron mobility transistor enhancement mode process and achieves a measured small signal gain of 10.5 dB, output power at 1-dB compression point ( $P_{1\,{\text{dB}}}$ ) of 27 dBm, and measured maximum PAE of 38%. The PAE at 6-dB PBO and 8-dB PBO are 32% and 28.5%, respectively. Furthermore, the PAE at 6-dB PBO maintains higher than 28.4% over a 1-GHz bandwidth from 29.25 to 30.25 GHz.

The molecular dynamics simulations method is applied to survey the deposition and annealing processes of ZrxCu100-x film on a Cu(001) surface. The influences of ZrxCu100-x compositions and depths on the force, deformation behavior, pile-up, and hardness are investigated using nano scratching and nanoindentation processes. We find out that the structure of ZrxCu100-x alloy has stability increases when decreasing the Zr content. The surface roughness of Zr-Cu film increases when improving the Zr content. After annealing, the morphology surface of the Zr-Cu amorphous alloy becomes smoother. The scratching forces and average friction coefficient of the Zr20Cu80 film surge as the scratching depth rises. While the pile-up height, normal force, and friction force decrease as increasing the Zr ratio. Under the plastic and elastic deformations, shear transformation zones are formed in the Zr-Cu amorphous film. While in the nanoindentation process, the hardness of ZrxCu100-x film amorphous film tends to decrease when increasing the Zr content.

The purpose of this research is to shed more light on the intermixing and deformation of an Au nanoparticle during a deposition process on a Cu substrate by using molecular dynamics simulation. This study investigates the influence of surface conditions, incident angle, speed impact, and diameter of Au particle on the deformation behaviors, temperature, and the bonding between it and Cu substrate. The results reveal that after deposition, the high-stress zone, structure change, and dislocation mostly concentrate at the interfacial zone. The Au particle's deformation behaviors and dislocation evolutions closely relate to three stages, which are impacting, after impact, and relaxation stages. Moreover, the higher level of textured surface or the rougher surface generates a greater level of intermixing, flattening ratio, and bonding between the Au particle and Cu substrate. Decreasing the incident angle leads to an increase in the flattening ratio value and the Au–Cu bonding. While increasing the incident velocity from 100 to 700 m/s results in a greatly higher rate of deformation, Au–Cu bonding, and penetration depth. Interestingly, reducing the particle size helps to improve the rate of deformation.

This Letter describes a super-oscillatory lens (SOL), with concentric ring-type metallic slits photolithographically fabricated on a glass substrate, that can function at subterahertz frequencies. The SOL has been investigated both experimentally and theoretically and demonstrates a spatial resolution of 1.5 mm ( 0.5 λ ), which is 0.45 times the diffraction limit, with a focal length of 75 mm ( 25 λ ) at 100 GHz ( λ = 3 m m ). Furthermore, the depth of focus of the lens was measured to be 47 mm, which is 10.8 times larger than that of a conventional lens. This type of SOL, with subdiffraction focusing, is thus highly effective for use in industrial inspections with millimeter and terahertz waves.

This paper presents a highly efficient power transfer system based on a co-design of a class-E power amplifier (PA) and a pair of inductively coupled Helical coils for through-metal-wall power transfer. Power is transferred wirelessly through a 3.1-mm thick aluminum barrier without any physical penetration and contact. Measurement results show that the class-E PA achieves a peak power gain of 25.2 dB and a maximum collector efficiency of 57.3%, all at 200 Hz. The proposed system obtains a maximum power transfer efficiency of 9% and it can deliver 5 W power to the receiver side through the aluminum barrier.

Measurement resolution is one of the most important elements for industrial applications. However, conventional lenses for terahertz (THz) or millimeter-wave cannot achieve high resolution due to the diffraction limit. Here, we demonstrate two types of super-oscillatory lenses that are very effective for sub-diffraction focusing at THz.

In this paper, we present two different approaches to design a driver for high gain Doherty power amplifiers (DPAs): single driver and dual-driver topologies. Detailed analysis and quantitative comparison between the two approaches are proposed. In particular, the single driver topology is preferred when the output Doherty stage has a reasonable gain. On the other hand, when the output stage has low gain, the dual driver approach is required to prevent significant efficiency reduction. Two DPA circuits at two different frequency ranges have been fabricated in a 0.15-μm Gallium Arsenide (GaAs) process to verify the concept. The single driver DPA at 10 GHz achieves at a measured gain of 19.2 dB and the maximum power of 27 dBm. The peak power added efficiency (PAE) and PAE at 6-dB power back-off (PBO) are 43% and 32%, respectively. On the other hand, the dual driver DPA at 28 GHz exhibits 15 dB of gain, 28.2 dBm output power with an associated peak PAE of 37%. To the best of the authors’ knowledge, our DPA prototypes achieve the highest gain of all reported DPAs at similar frequency ranges.

A compact wideband Ka-band monolithic microwave/ millimeter-wave integrated circuit (MMIC) power amplifier (PA) is demonstrated using a 0.15-μm pseudomorphic high electron mobility transistor (pHEMT) Gallium Arsenide (GaAs) process. The proposed harmonic load-pull and radial stub matching technique have been employed to achieve wideband and high-efficiency performance. The fabricated PA exhibits a measured output power of 24 dBm, gain of 20 dB and 35% power added efficiency (PAE). The PA has a wideband performance in which the power maintains higher than 23 dBm, and the PAE is higher than 30% over a wide frequency range from 25 to 34 GHz.

In this paper, we surveyed the effect of graphite thickness, impact velocity, substrate temperature, angle tilt of particle, incident angle, and Ni crystalline faces on the formation of graphene flakes, temperature, von Mises stress, and deformation. In the deposition process, graphene flakes are formed due to the impaction and attaching between the Ni substrate and graphite particles. The results reveal that there is a critical impact velocity leading to the graphene flakes that separated from the graphite particle and attached to the Ni substrate. The critical impact velocity decreases as increasing the thickness of graphite particles from 9 to 18 layers. In addition, the substrate temperature of the impact region and numbers of deposited graphene layers rise with the impact velocity increases. Notably, the elastic and plastic deformations of Ni substrate happen in the deposition process with high impact velocity. Furthermore, some dislocations are formed during and after the impact of the particle. The high-stress regions concentrate in the deposited graphene flakes and interfacial zone. The deposited graphene layer on Ni(001) creates a more stable structure than on surfaces Ni(111) and Ni(110). The graphene layer is successfully formed in the deposition process at an angle tilt from 0° to 10°.

The authors present the design and development of a two stage Doherty power amplifier (DPA) in the Ka-band. The amplifier is fabricated in a 0.15-μm gallium arsenide (GaAs) pseudomorphic high electron mobility transistor (pHEMT) process. The DPA has a centre frequency of 26.6 GHz, a measured small signal gain of 10.5 dB, output power at 1-dB compression point (P1 dB) of 26.9 dBm, maximum power added efficiency (PAE) of 42%, and PAE of 32% at 6 dB back-off power. To the best of the author's knowledge, this DPA is the first millimetre-wave (mm-wave) power amplifier to achieve a record 32% PAE at 6-dB back-off power from 26.9 dBm at Ka-band.

This letter presents the design and measured results of novel wideband, highly linear gate-pumped distributed downconverter mixers. The circuit is realized in a 0.25-μm, Enhancement-mode GaAs pseudomorphic High Electron-Mobility Transistor process which requires no negative voltage supply. Two cells with different biases in parallel are used to achieve third-order intermodulation product cancelation. Each cell utilizes the distributed topology to absorb the first-order gate-source capacitances C gs1 . Two mixers are demonstrated: 1) a single-ended (SE) mixer and 2) a single-balanced (SB) mixer. The SE and SB mixers achieve a measured third-order input intercept point above 30 dBm in the RF frequency ranges from 6-26 GHz and 6-20 GHz, respectively. Both mixers show a conversion loss of less than 10 dB. The balanced mixer exhibits more than 30 dB of LO-RF isolation.

Molecular dynamics (MD) simulations have been employed to simulate the deposition process of Cu and Ni atoms on the Ni (001) substrate with the different compositions in the CuxNi100-x film. Then, the mechanical characteristics of CuxNi100-x/Ni substrate are investigated during the nanoindentation process. The deformation behavior in the nanoindentation process is also investigated when the parameter for velocity, temperature changes. The lattice constant of CuNi alloy increases as Cu content in CuNi alloy rising. In the case of different contents of Cu atoms, the force, hardness of the CuxNi100-x/Ni substrate reduce as increasing the content of Cu. The shear strain and von Mises stress region increase as increasing the temperature and the loading velocity after the loading process. The plastic and elastic deformation of the CuxNi100-x/Ni substrate formed during nanoindentation. The force and hardness of the CuxNi100-x/Ni substrate reduce as increasing the temperature. In addition, with the higher loading speed, the force and hardness values become larger. The dislocation density increases as increasing the indentation depth after the loading process.

Molecular dynamics (MD) simulation is used to simulate the deposition and annealing process of Cu atoms on the Ni (001) trench. The results indicate that the curvature of profile and surface roughness of the Cu layer film decrease as increasing the substrate temperature and/or incident energy. The surface roughness of the deposition Cu film is variability as increasing the incident angle from 0° to 30°. In the growth process, the intermixing occurs at the interface between Cu atoms and Ni trench, and the length increases as the increasing of substrate temperature and/or incident energy. These phenomena may be attributed to the enhanced atomic mobility for higher incident energy and thermal annealing. The peak-to-peak distances of g(r) clearly indicate that the crystal structure of Cu–Ni atoms after the annealing process is improved, and still FCC structure. The dislocation is formed during the deposition process and affected by the substrate temperature, as well as the incident energy. The annealing treatment reduces the residual stress in the deposited Cu layer. The formation of the vacancies appears during the deposition process. After the annealing process, the Cu–Ni atoms become more orderly in the crystal lattice, many vacancies and voids are destroyed. In addition, the surface of the Cu film layer becomes smoother.

A new generation of millimeter-wave heterodyne imaging receiver arrays has been developed and demonstrated on the DIII-D electron cyclotron emission imaging (ECEI) system. Improved circuit integration, improved noise performance, and enhanced shielding from out-of-band emission are made possible by using advanced liquid crystal polymer (LCP) substrates and monolithic microwave integrated circuit (MMIC) receiver chips. This array exhibits ∼15 dB additional gain and >30× reduction in noise temperature compared to previous generation ECEI arrays. Each LCP horn-waveguide module houses a 3 × 3 mm GaAs MMIC receiver chip, which consists of a low noise millimeter-wave preamplifier, balanced mixer, and IF amplifier together with a local oscillator multiplier chain driven at ∼12 GHz. A proof-of-principle partial LCP instrument with 5 poloidal channels was installed on DIII-D in 2017, with a full proof-of-principle system (20 poloidal × 8 radial channels) installed and commissioned in early 2018. The enhanced shielding of the LCP modules is seen to greatly reduce the sensitivity of ECEI signals to out-of-band microwave noise which has plagued previous ECEI studies on DIII-D. The LCP ECEI system is expected to be a valuable diagnostic tool for pedestal region measurements, focusing particularly on electron temperature evolution during edge localized mode bursting.

In this paper, for the first time we develop and benchmark the performance of three down-converting Field Effect Transistor (FE T) resistive mixers at millimeter wave (mm W) frequencies employing $\pmb{0.15-\mu \mathrm{m}}$ enhancement (E)-mode Gallium Arsenide (GaAs) pseudomorphic high electron mobility transistors (pHEMTs), depletion (D)-mode GaAs pHEMTs, and D-mode Gallium Nitride (GaN) pHEMTs. Our experimental results at 27 GHz demonstrate that the E-mode mixer achieves the highest reported input 3rd order intercept point (IIP3) of 37.5dBm at mm W frequencies to the best of our knowledge. Also, operating at the same LO drive up to 20 dBm, the E-mode GaAs mixer impressively out performs both the D-mode GaAs and GaN mixers.

We describe a wideband, bandpass distributed amplifier designed in an indium phosphide (InP) heterojunction bipolar transistor (HBT) process. A HBT gain cell containing a double stacked-HBT stage is used along with a new bandpass architecture to design a bandpass distributed amplifier with a bandwidth of 65–145 GHz. The proposed amplifier exhibits a simulated average gain of 12.5 dB and a maximum output power of 17 dBm.

A K-band monolithic microwave integrated circuit (MMIC) transmit and receive (T/R) single pole double throw (SPDT) switch with low insertion loss, high isolation and ultra-high output power is demonstrated using 0.15- $\mu\text{m}$ Gallium Arsenide (GaAs) technology. A shunt field effect transistor (FET) configuration is used to provide low insertion loss and high isolation while the stacked-FET is employed to improve power handling capability. The novel GaAs switch exhibits a minimum measured insertion loss of 1.4 dB and less than 2.5 dB from 22 GHz to 26 GHz as well as 44 dB isolation. The measured input 1-dB power compression point $({P}_{1\, \mathrm{dB}})$ exceeds 4 W.

An ultra-compact watt-level Ka-band monolithic microwave integrated circuit (MMIC) power amplifier (PA) is demonstrated using a 0.15 $\mu\text{m}$ Gallium Arsenide (GaAs) stacked field effect transistor (stacked-FETs) configuration. The fabricated PA exhibits 31.5 dBm output power, 17 dB gain and 33% power added efficiency (PAE). The bandwidth is from 26 GHz to 31 GHz. The PA achieves 0.7 Watt/mm2 power density at 28 GHz. To the best of our knowledge, this PA achieves the highest power density among reported GaAs Ka-band PAs.

We propose an extended range Doherty power amplifier (DPA) to achieve high efficiency at 9-dB power back-off (PBO) using a novel loading impedance range. The proposed loading impedance range enables the auxiliary transistor to deliver more current so that symmetric devices can be used in the DPA and results in a compact and low loss output combining circuit. A 20-Watt DPA using Gallium nitride high electron mobility transistors (GaN HEMTs) at 3.5 GHz has been developed to demonstrate the concept. Measurements show power added efficiency (PAE) of 69% at 42.9 dBm saturation output power, PAE of 55% at 9-dB PBO, and gain of 12 dB. We believe our proposed DPA has the highest 9-dB PBO PAE of 55% among reported GaN DPA's.

In this paper, we present a compact Doherty power amplifier (DPA) in a 0.15-μm enhancement mode (E-mode) Gallium Arsenide (GaAs) pseudomorphic high electron mobility transistor (pHEMT) process at Ka-band. The 2-stage DPA uses an integrated input broadside coupler to miniaturize the die size to 2.86 mm2. The monolithic millimeter-wave integrated circuit (MMIC) DPA exhibits a measured output power of 26 dBm and a measured average gain of 12 dB. The gain bandwidth covers from 25.5 to 33 GHz. The measured peak power added efficiency (PAE) is 40% and the PAE at 6 dB output power back-off is 29%. Moreover, an adjacent channel power ratio (ACPR) of −45 dBc has been measured using a 20 MHz digitally modulated signal and digital predistortion (DPD).

This paper presents a novel, dual-mode, reconfigurable, fully integrated double-balanced ring mixer. The change in DC bias of the mixer core leads to two operation modes: a passive mixer and an active mixer with variable conversion gain. In addition, an active IF balun using a DC-coupled differential pair configuration is designed to cover IF frequency from DC to 4 GHz. The measurement results show that the conversion gain can change from −6 dB to 6 dB over RF frequency range of 742 GHz. The measured input third order intercept point (HP3) is 5 dBm and the measured input 1-dB compression point (IP1dB) is 5 dBm at the highest conversion gain mode with 4-dBm LO drive. At the lowest conversion gain mode, the HP3 is 20 dBm and IP1dB is 12 dBm with 13-dBm LO drive.

We present a stacked-FET monolithic millimeter-wave (mmW) integrated circuit Doherty power amplifier (DPA). The DPA employs a novel asymmetrical stack gate bias to achieve high power and high efficiency at 6-dB power back-off (PBO). The circuit is fabricated in a 0.15-µm enhancement mode (E-mode) Gallium Arsenide (GaAs) process. Experimental results demonstrate output power at 1-dB gain compression (P 1dB ) of 28.2 dBm, peak power added efficiency (PAE) of 37% and PAE at 6-dB PBO of 27% at 28 GHz. Measured small signal gain is 15 dB while the 3-dB bandwidth covers from 25.5 to 29.5 GHz. Using digital predistortion (DPD) with a 20 MHz 64 QAM modulated signal, an adjacent channel power ratio (ACPR) of −46 dBc has been observed.

In this paper, we report a wide bandwidth low noise amplifier (LNA) fabricated in a 0.15 μm enhancement mode (Emode) gallium arsenide (GaAs) pseudomorphic high electron mobility transistor (pHEMT) process. The lna employs source degeneration along with a resistive feedback network to achieve low noise figure (NF) over a wide bandwidth. Experimental results show that the LNA exhibits a maximum gain of 30 dB and maintains higher than 25 dB from 14 to 31 GHz. The measured minimum NF is 1.25 dB along with 17.5 dBm output 1-dB compression point (OP1dB) and 28.5 dBm output 3rd order intercept point (OIP3).

We propose a new modulating load range for a Doherty power amplifier (DPA) that will maintain maximum drain voltage swing and consequently peak efficiency in over 6-dB power back-off (PBO). At 6-dB PBO, the real part of the new modulating load seen by the main amplifier is less than 2∗Ropt. The new load range allows for the design of a compact, low loss output matching and combiner circuit and a simple single drain bias line for the main and auxiliary amplifiers. The proposed 2-stage DPA using the new modulating loads is designed at 15 GHZ in a 0.15 μm enhancement mode (E-mode) Gallium Arsenide (GaAs) pseudomorphic high electron mobility transistor (pHEMT) process. The proposed DPA achieves a measured Psat of 27 dBm, a peak power added efficiency (PAE) of 41% and a PAE of 34% at 6 dB PBO with a gain of 17 dB.

This communication presents for the first time a 16-element planar X-band bidirectional antenna array for beamforming applications. The planar (2D) antenna array is comprised of planar polygon slot antenna elements that utilize a metamaterial inspired reactive coupling element. Simulation and measurement results are presented for both a single antenna element and a 16-element planar array, which resides on a Liquid Crystal Polymer (LCP) substrate. Successful comparison between measured and simulated results verifies that the single antenna element achieves a 10 dB return loss bandwidth of 17.5% and the planar antenna array achieves a 10 dB return loss bandwidth of 25% both at a center frequency of approximately 11 GHz. The measured gain of the planar antenna array is more than 14.5 dBi with an efficiency of 65%. The overall size of the planar antenna array is 3.3λ° × 3.6λ° × 0.0093λ° at 11 GHz.

The design and fabrication of a W-band 64 element slot antenna array based on the substrate integrated waveguide structure is presented in this communication. The prototype antenna array is fabricated on a liquid crystal polymer substrate using standard printed circuit board (PCB) manufacturing processes. Characterization of the unbalanced antenna is accomplished through the use of a millimeter-wave diode detector circuit, which is integrated onto the antenna array. Measurements show a beamwidth of approximately 13.2°. The maximum sensitivity of the antenna array with the diode detector is 121 mV/mW at 96 GHz. The total size of the antenna array with detector circuit is 4 × 3 cm2. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1825–1830, 2013

We demonstrate the design of a linear and high efficient power amplifier (PA) by using different gate bias voltages for parallelly combined Gallium Nitride (GaN) high electron mobility transistors (HEMTs). The experimental results show that the linearized PA achieves the gain flatness of 0.3 dB over a 35 dB power range and has a measured sharp output power at 1 dB compression point (P1dB) of 38.5 dBm, less than 2 dB below the saturated power (PSAT). The measured adjacent channel power ratio (ACPR) of the proposed linearized PA shows up to 8 dB improvements over the PA biased ~ class A (47% $I_{\mathrm {dss}}$ )

A 6–46 GHz balanced distributed doubler fabricated in a low-cost 0.25 μm GaAs pHEMT process is presented in this paper. For the first time, a distributed topology combining with a stacked-FET structure for a frequency doubler is used to realize a fully integrated wideband, high output power frequency doubler. The proposed frequency doubler achieves a measured gain of 8–14 dB, a maximum output power of 12–19 dBm and a typical fundamental suppression of 15 dBc from 6–46 GHz.

We demonstrate the development of a highly linear Ka-band power amplifier (PA) using second harmonic injection at the gate of a pseudomorphic high mobility electron transistor (pHEMT). The second harmonic injection PA (HI PA) achieves a measured gain of 18.5 dB and P 1dB of 23.5 dBm at 28.5 GHz. Compared to the same PA without second harmonic injection, the HI PA has a 3.5 dB higher in P 1dB and a 12 dB improvement in the third-order intermodulation distortion (IM3). To the best of our knowledge, our 2nd harmonic injection PA is the first demonstration of the technique at millimetre-wave frequencies.

A stacked-FET power amplifier (PA) with harmonic- tuned output matching network is demonstrated using a 0.15-µm Gallium Arsenide (GaAs) technology. The fabricated PA exhibits 28.5 dBm output power, 12 dB gain and 38.4% power added efficiency (PAE). To the best of our knowledge, this is for the first time stacked-FET technique is used in combining with harmonic-tuned output network to achieve high PAE and high power density simultaneously in a GaAs PA.

Author(s): Pham, BL; Ta, HH; Pham, AV; Leoni, RE; Leviatan, Y | Abstract: In this study, the authors present the design and development of a novel ultra-wideband coupled-line balun on a multilayer liquid crystal polymer substrate. The balun is designed using a quarter wavelength (λ/4) asymmetric broadside coupled line. The defected ground structure and a lumped phase compensation circuit are developed to achieve wide bandwidth performance for the balun. The balun has a measured bandwidth ratio of 23:1, from 80 to 1860 MHz. Within the operating bandwidth, the experimental results demonstrate that the balun achieves an input return loss of better than 10 dB, an insertion loss of better than 1 dB, an amplitude imbalance of better than ±0.4 dB and a phase imbalance of better than ±10°. The size of the balun is 40.64 mm × 40.64 mm or 0.22 λg × 0.22 λg, where λg is the guided wavelength at the centre frequency of 970 MHz.

Electronics packages provide housing, protection, electrical interconnections, thermal dissipation, and assembly for integrated circuits and devices. At high frequency, cavity packages are used more often than over-molded plastic packages to achieve lower electrical losses. The major drawback of cavity packages is the open area that water and other contamination can be accumulated on the surface of a packaged device to cause degradation such as corrosion.

In this paper, we present the design and development of thin-film liquid-crystal-polymer (LCP) surface-mount packages for Ka-band applications. The packages are constructed using multilayer LCP films and are surface mounted on a printed circuit board (PCB). Our experimental results demonstrate that the package feed-through transition including a PCB launch and bond wires achieve a return loss of better than -20 dB and an insertion loss of less than 0.4 dB around Ka-band. We achieve a measured port-to-port isolation of the package to be more than 45 dB across the Ka-band. We demonstrate the package feed-through circuit model by comparing the simulation of model and bare die measurement data to a packaged amplifier measurement. Finally, we report an LCP cavity that has a measured fine leak rate of 3.6 times 10-8 atmldrcc/s.

We present the design and development of an organic package that is compatible with fully released RF microelectromechanical systems (MEMS). The multilayer organic package consists of a liquid-crystal polymer film to provide near hermetic cavities for MEMS. The stack is further built up using organic thin-film polyimide. To demonstrate the organic package, we have designed and implemented a 2-bit true-time delay X-band phase shifter using commercially available microelectromechanical switches. The packaged phase shifter has a measured insertion loss of 2.45 plusmn 0.12 dB/bit at 10 GHz. The worst case phase variation of the phase shifter at 10 GHz is measured to less than 5deg. We have also conducted temperature cycling (-65degC to 150degC) and 85/85 to qualify the packaging structures.

We present performance improvement in InP traveling-wave modulators (TWMs) using a periodic ion implantation on coplanar waveguide. Fabricated TWMs show the successful velocity and impedance tuning with return loss of lower than −12dB and reduced effective microwave refractive index of approximately 4 across the measured frequency range up to 50GHz. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2151–2155, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23607

In this paper, we present the design and fabrication of ultra-wideband (UWB) baluns embedded in multilayer liquid crystal polymer (LCP) flex. Fabrication techniques are demonstrated for processing these commercially available LCP thin-films by standard PCB equipments. Variations in the LCP thin-film thickness are characterized and compared before and after lamination. Results show good dimensional stability of the material, a critical factor in controlling the line impedances and performance of the balun. Electrical results of these baluns show bandwidths exceeding 3.1-10.6 GHz with less than 1 dB insertion loss, and amplitude and phase imbalance less than 1.2 dB and 2deg, respectively. These baluns are ideal for applications in UWB communication systems specified by the IEEE 802.15.3a standard.

We present the design and fabrication of an ultra-wide bandwidth balun on a multilayer organic Liquid Crystal Polymer substrate. Using a novel U-shaped defected ground structure and a single inductor, the balun achieves a measured insertion loss of less than 1dB and return loss of better than 10dB from 50MHz to more than 3 GHz. Within the measured 46⋆1 bandwidth ratio from 50MHz to 2.3GHz, the amplitude and phase imbalance are less than 1dB and 8°, respectively. This proposed balun has a compact size of 35mm × 51mm. To our knowledge, the balun has the largest bandwidth ratio reported to date on multilayer printed circuit without ferrites.