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This paper presents the design and simulation of two single-stage power amplifiers (PAs) to determine the performance capabilities of WIN Semiconductors 0.15 μm Gallium Nitride (GaN)-on-SiC process. Subsequently a 28 GHz two-stage PA is presented for potential integration into 5G transceiver applications. A 2×100 gate-width device was used to develop a driving stage PA (MMIC1) which produced a simulated 12.8 dB small signal gain at the desired 28 GHz. A 4×100 gate-width device was used to characterize an output stage PA (MMIC2) producing 33 dBm power out, PAE of 41%, and a power gain of 11.2 dB. The subsequently designed two-stage PA, MMIC3, combines MMIC1 and MMIC2 and provides a peak small signal gain of 22.5 dB, peak power output of 33 dBm, peak PAE of 31% and peak power gain of 22.4 dB.

A wideband resistive mixer from 30 GHz to 56.5 GHz implemented in WIN Semiconductor's newly released 0.15μm GaN/SiC HEMT process is presented in this paper. The mixer exhibits a conversion loss of 10 dB at the midband for an optimum input LO power of 12 dBm. The LO-IF and RF-IF isolations are higher than 49 dB and 34 dB respectively. Mixer's input 1dB compression point is 18 dBm. The chip size including the pads is 1 mm2, and the circuit's active area is only 0.29 mm2.

A 0.13 SiGe upconverter circuit is presented that is suitable for use in broadband millimetre-wave transmitters and active phased arrays. The circuit accepts four differential IF inputs (I+, I−, Q+, Q−) in the frequency range of DC to 13 GHz. An off-chip X-band LO passes through an on-chip tripler before being used to drive the image rejection mixer. The resultant output may be placed anywhere in the frequency range of 25 to 42 GHz. When all four inputs are utilised the RF signals are combined passively at the mixer outputs to achieve an output referred P1dB compression point of +4.4 dBm without the need for additional amplifiers in the RF signal path. This paper highlights the measured bandwidth and single-tone compression characteristic of the circuit. Layout techniques are also briefly described.

In this paper, a 39 GHz power amplifier (PA) implemented in WIN Semiconductor's newly released 0.15 μm GaN HEMT process is presented. The load-pull simulation for power at 39 GHz for a 4×100 gate width transistor is also shown. The electromagnetic (EM) simulation of the designed two-stage PA shows a power gain of 17 dB at 39 GHz, 21% PAE and 31 dBm saturated output power.

Measurement results performed on a GaN high-electron-mobility transistor that show the presence of a double-energy-level (DEL) trap center in the device are presented. A novel, yet simple, circuit implementation of a DEL trap center in an FET is presented that is immediately extendableto a trap centerwithmore than two energy levels. The model is based on the Shockley–Read–Hall statistics of the trapping process. The implementation is suitable for both time-domain and harmonic-balance simulations. Simulation results validate the proposed model.

The temperature response of field-effect transistors (FETs) to instantaneous power dissipation has been shown to be significant at high frequencies, even though the self-heating process has a very slow time constant. This affects intermodulation at high frequencies. A major difficulty in characterizing the self-heating process in microwave FETs is to differentiate between the self-heating and charge-trapping rates. An iso-trapping measurement technique is proposed by which it becomes possible to characterize the self-heating process in an FET in isolation from the effect of the charge-trapping process in the FET. The results of iso-trapping measurements performed on a GaN high-electron-mobility transistor are presented, and used to successfully characterize the self-heating process.

© 2016 IEEE. This paper presents a theoretical analysis for location estimation of a wireless capsule endoscope (WCE) in the small-intestine region. Under three different shadowing scenarios by assuming standard deviation of the shadowing with the constant variance, parameter-dependent variance, or correlated and parameter-dependent variance, analytical formulas are derived for the Cramér-Rao lower bound (CRLB) for capsule positioning when distance and azimuth angle measurements are employed to estimate the location of the capsule. The CRLB analysis can be employed to quantify the best achievable location estimation performance. We also present some numerical results to show the CRLB for three scenarios. The results show that in the most realistic scenario, when the shadowing is spatially correlated and distance dependent and the standard deviation of noise is 7 dB, the maximum square root of CRLB is 3.8 mm. Moreover, the square root of CRLB experiences its minimum value of 2 mm, when the capsule is away from its first location about half of the capsule length. Overall, the result of this paper suggests that it is possible to use received signal strength such as measured by a radar system for location estimation of a WCE.

A circuit implementation of a single-energy-level trap center in an FET is presented. When included in transistor models it explains the temperature-potential-dependent time constants seen in the circuit manifestations of charge trapping, being gate lag and drain overshoot. The implementation is suitable for both time-domain and harmonic-balance simulations. The proposed model is based on the Shockley-Read-Hall (SRH) statistics of the trapping process. The results of isothermal pulse measurements performed on a GaN HEMT are presented. These measurement allow characterizing charge trapping in isolation from the effect of self-heating. These results are used to obtain the parameters of the proposed model.

A self-biased balanced frequency doubler is presented in gallium arsenide (GaAs) with more than 38 dB fundamental suppression and broad bandwidth from 22 to 40 GHz at its output. The combination of both large bandwidth and excellent harmonic rejection was achieved by applying a transformer balun with a high degree of symmetry and minimal capacitive coupling. The balun alone has a gain and phase imbalance of less than 0.3 dB and 0.7° respectively from 2 to 25 GHz. The conversion gain of the doubler with the balun is -2 to -5 dB across the output frequency range. The highest output power is approximately 8 dBm between 18 and 20 GHz, with 10 dBm input. This work features the highest fundamental rejection across the band compared to the previously reported broadband GaAs doublers, enabled by the excellent balance of the balun.

A one-dimensional periodic structure comprising of eight unit cells each having two metallic patches sandwiched between microstrip line and ground plane has been investigated. Patches bearing dissimilar dimensions present distinct reactive loads, determined by their respective areas, to generate relatively wider bandgap. Patches can be selectively connected to ground or left floating through a combination of vias and externally controlled FET switches. Dispersion analysis of the structure has been carried out to determine the propagating modes of the line for all four possible states of the unit cell. A top-down, design guide approach has been adopted with the effect of parameters determining performance attributes captured. The proposed structure acts as an all pass filter from DC to 19.5 GHz with all patches floating and exhibits stopband characteristics from 6 to 19.5 GHz with different combinations of the switches offering an overall stop bandwidth greater than 100%. The proposed structure offers tunability from no bandgap to bandgap with added advantages of band switching capability with double the number of unique reconfigurable switch patterns as compared to conventional single patch structures.

A compact balanced frequency doubler with more than 35 dB odd-harmonic rejection and fractional bandwidth of 73% is presented in this letter. Wide bandwidth and high odd-harmonic suppression is achieved by adopting a new technique for the transformer balun design, resulting in a very low magnitude imbalance of 0.13 dB and a phase imbalance of 0.4° over 7–15 GHz. The balun performance is improved by offsetting the radius of the primary and secondary coils, which reduces the parasitic coupling capacitance. The input and output frequency ranges for the doubler are 7–15 GHz and 14–30 GHz respectively. The circuit was fabricated in 0.13- $\mu \text{m}$ SiGe technology. The chip size is 0.6 mm $\times \, 0.4$ mm.

The results of measurements performed on a GaN high electron-mobility transistor (HEMT) by two different pulse-measurement techniques are presented. By performing two-stage pulse measurements, two distinct current-injection mechanisms responsible for triggering the trapping process are identified. By performing three-stage pulse measurements, the trap center at which the trapping process occurs is identified to be a double-energy-level trap center, which is a trap center with two distinct energy levels between which there is an interaction. This result has a significant impact on the design of more accurate large signal models for GaN HEMTs.

Conventional and additive manufacturing (three-dimensional [3D] printing) techniques for a dual-ridged horn antenna (DRHA) are presented. The different aspects of the conventional manufacturing of a DRHA and the limitations incurred during additive manufacturing are discussed in detail. The antenna design was further optimized for fused deposition modeling and was 3D printed using acrylonitrile butadiene styrene (ABS). The polymer-based print was painted with nickel-based aerosol spray. The coaxial transition is also included in the 3D printed prototype. The antenna was manufactured with the intention of improving the learning and education of electromagnetism and antennas of undergraduate students using a low-cost personal desktop 3D printer. The painted DRHA has a 10 dB return-loss bandwidth of 6621 MHz (1905–8526 MHz) with a peak gain of 11 dBi. The average cross-polarization isolation achieved was more than 25 dB. Rapid prototyping was possible with additive manufacturing, and limitations were addressed with conventional machining processes whenever required. This prototype is the first known ABS-based horn antenna with the coaxial transition embedded into it. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2110–2117, 2016.

An on-chip resonator is designed and fabricated using a standard 0.13- $\mu \text{m}$ SiGe technology for millimeter-wave applications. The designed resonator is based on a unique structure, which consists of two broadside-coupled meander lines with opposite orientation. The equivalent $LC$ circuit of the resonator is given, while the impact of the structure on the resonance frequencies is investigated. Using this structure along with capacitors, a compact bandpass filter (BPF) is also designed and fabricated. The measured results show that the resonator can generate a resonance at 57 GHz with the attenuation better than 13.7 dB, while the BPF has a center frequency at 31 GHz and a insertion loss of 2.4 dB. The chip size of both the resonator and the BPF, excluding the pads, is only 0.024 mm2 ( $0.09 \times 0.27$ mm $^{2})$ .

A 3D printed dual-ridged horn antenna (DRHA) is presented. The antenna design is optimized for additive manufacturing and is 3D printed using acrylonitrile butadiene styrene (ABS) and then painted with nickel based aerosol spray. The coaxial transition is also included in the 3D printed prototype. The antenna was manufactured with the intention of improving learning and education of electromagnetism and antennas for undergraduate students using a low-cost personal desktop 3D printer. The painted DRHA has a 10 dB return-loss bandwidth of 6621 MHz (1905 MHz–8526 MHz) with a peak gain of 11 dBi. This prototype is the first known ABS-based horn antenna with the coaxial transition embedded into it.

A higher frequency, over 2 GHz, is suggested for current 4G or 5G wideband applications. By adopting a unique gain control method, an analog-controlled variable-gain amplifier (VGA) with an accurate dB-linear characteristic is presented. The designed VGA not only features large bandwidth, but also has accurate gain adjustment with a relatively wide control voltage range. The VGA has a measured gain range of 24 dB, of which 17.3 dB is dB-linear with less than $\pm$ 0.3-dB gain error. The $-$ 3-dB bandwidth is relatively constant from 2 to 2.2 GHz for the entire dB-linear range. An output 1-dB compression point of 1.8 dBm and a noise figure of 24 dB are measured. Due to the simple structure, the current consumption of the VGA core is only 2.9 mA from a 1.2-V supply, and the size is only ${\hbox{225}}\ \mu{\hbox{m}}\times {\hbox{45}}\ \mu{\hbox{m}}$ , excluding pads. Moreover, the robustness of the designed VGA is verified by means of Monte Carlo simulation.

Transient gate resistance thermometry is employed to characterise the time domain response of a GaAs pHEMT under pulsed conditions. Self heating is observed from hundreds of nanoseconds to hundreds of milliseconds. A TFR-heated test structure is used to develop a 3-D finite-element thermal model that scales with power density and gate periphery. Thermal coupling between gate fingers in a multi-finger device is measured, and then further investigated via simulation. The model's application to thermal optimisation of devices and circuits is discussed.

A folded edge-coupled transformer balun is presented with excellent balance and 3-dB bandwidth from 9 to 20 GHz. Three structures were simulated; straight, folded, spiralled; to study the trade-off between the circuit size and balance performance. A simplified lumped equivalent circuit model of the transformer balun is also shown. The transformer balun was implemented with two-port characterization structures to accurately measure the balance. The measured magnitude and phase imbalances are less than 0.3 dB and 0.7° from 2 to 25 G Hz, surpassing previously reported results for GaAs baluns. The balun was fabricated in a $0.1\ \mu \mathrm{m}$ GaAs pHEMT technology and occupies 0.24 mm2. This paper also highlights that the edge-coupling is preferred for GaAs technology baluns due to restrictions in metal fabrication.

International audience; —The strongest-cell criterion has been extensively used for handover algorithms during the last cellular-network generations. When network topologies become multi-layered, it results in abrupt behaviors such as the ping-pong effect as a consequence of the power gap between tiers and their irregular deployment. This effect not only affects users' quality of experience but also introduces a significant network overhead. Therefore, we propose an original handover algorithm based on predicted incomplete channel states from a Radio Environment Map to reduce this effect. The proposed algorithm is user triggered, network assisted, and fully backward compatible with LTE-A. Moreover, we evaluate the performance of our proposed algorithm against LTE-A in a two-tier cellular network for different user speeds following the guidelines outlined by the 3GPP on diverse matters (channel, mobility, wrapping, etc.). When applying realistic timing, our results reveal a highly substantial improvement in the number of ping-pong handovers regardless of the handover policy adopted in comparison to LTE-A without sacrificing users' experience; for instance, we obtain at least an order of magnitude decrease in the ping-pong rate at the expense of losing less than 9 percent in spectral efficiency.

A 0.1 Watt GaAs pre-amplifier has been developed with broadband match, gain, and power compression characteristics spanning 28 to 47 GHz. Flat gain was achieved by choosing a balanced topology and selectively mismatching the input and inter-stage networks at the low end of the band. The gain is 15.7 dB with 1.4 dB ripple. Input and output matches are −17 dB and −22 dB respectively. The Psat is +22.0 dBm, P1 +19.4 dBm and the DC current is 160 mA from a 4 V supply. The amplifer is suitable for cascading to multiple-stages to achieve a low ripple, high gain frequency response for broadband electronic warfare applications.

The design of two transformer baluns is presented using different process technologies. Gallium Arsenside (GaAs) has been widely used for microwave circuits over the past few decades for its high performance. Silicon Germanium (SiGe) is an emerging technology that offers performance similar to GaAs and digital circuit integration. The differences between the metal and insulator layers are presented in the context of the balun design and its requirement for tight coupling between primary and secondary coils. A comparable performance was achieved between the two processes using electromagnetic simulation. The magnitude and phase imbalances were (0.05 dB, 0.5o) for GaAs and (0.05 dB, 0.2o) for SiGe between 10 and 20 GHz.

The temperature-dependent thermal conductivities of a GaAs pseudomorphic high-electron mobility transistor’s (pHEMT) substrate and epilayer regions are extracted to develop a 3-D finite-element-method thermal model. The thermal characterization is based on electrical gate-metal-finger temperature measurements of a customized GaAs pHEMT test structure. Heat flow from an integrated thin-film resistor is shown to be sensitive to the device’s substrate thermal conductivity, while heat flow from the device’s channel is most significantly affected by the epilayer region thermal conductivity. These observations are used in the formulation of the thermal parameter extraction technique, which serves as a useful and convenient device modeling tool that can be integrated into an engineering design flow. Specific knowledge about the semiconductor material fabrication process, which may be unavailable to the design engineer, is not required for accurate thermal characterization; this is the overriding advantage of the technique presented.

International audience; The advent of 5G networks, where a plethora of spectrum-sharing schemes are expected to be adopted as an answer to the ever-growing users' need for data traffic, will require addressing mobility ubiquitously. The trend initiated with the deployment of heterogeneous networks and past standards will give way to a multi-tiered network where different services will coexist, such as device-to-device, vehicle-to-vehicle or massive-machine communications. Because of the high variability in the cell sizes given the different transmit powers, the classical handover process, which relies solely on measurements, will lead to an unbearable network overhead as a consequence of the high number of handovers. The use of spatial databases, also known as radio environment maps (REM), was first introduced as a tool to detect opportunistic spectrum access opportunities in cognitive radio applications. Since then, REM usage has been widely expanded to cover deployment optimization, interference management or resource allocation to name a few. In this paper, we introduce a handover algorithm that can predict the best network connection for the current user's trajectory from a radio environment map. We consider a geometric approach to derive the handover and handover-failure regions and compare the current handover algorithm used in Long-Term Evolution with our proposed one. Results show a drastic reduction in the number of handovers while maintaining a trade-off between the ping-pong handover and the handover-failure probabilities.

Characterization of a wide-band transformer balun with low magnitude and phase imbalance is presented in this paper. Excellent balance over a large bandwidth is achieved by adopting two new techniques for the transformer balun design, resulting in a very low magnitude imbalance of 0.12 dB and phase imbalance of less than 1° over 30 to 60 GHz. The tradeoff between the insertion loss and the balance of the balun is investigated. First, the appropriate width of the primary and the secondary coils is selected for a reasonable insertion loss. Secondly, the radii of the primary and secondary coils were offset to reduce the parasitic coupling capacitance, thereby improving the balance of the differential signal. The balun is fabricated in 0.13 μιη SiGe technology. The balun is very compact with chip size of 0.2 mm × 0.145 mm.

In this paper, we present a spiral loop type antenna, implanted in the tibial bone. The antenna has been designed for fabrication on commercially available RT Duroid 6010 (ɛr=10.2) substrate and encapsulated in biologically compatible Polydimethylsiloxane (PDMS) material (ɛr=2.6). The antenna has a footprint of 2.6 mm × 2.6 mm and a height of 1.94 mm. The antenna operates at the 2.4 GHz ISM band with the peak gain of -36.2 dBi.

High data rate implantable wireless systems come with many challenges, chief among them being low power operation and high linearity. A low noise amplifier (LNA) designed for this application must include high gain, low noise figure (NF) and better linearity at low power consumption within the required frequency band. The down converter also requires a passive mixer to achieve low power and better linearity. In this paper, design is based on an Impulse Response (IR) Ultra-wideband (UWB) receiver operating at (3.1-5) GHz implemented in 0.25 μm CMOS Silicon on Sapphire (SOS). This paper reports the design and measurement of a UWB receiver with a designed and measured linearity of 17 dBm, a gain of 30.5 dB and a minimum NF of 4.5 dB, which make it suitable for implantable radio applications. © 2014 Published by Elsevier Ltd.

The thermal impact of device bias-state and structures (such as source connected field plates, gate-pitch, back-vias, and number of gate fingers) in AlGaN/GaN-on-Si high electron mobility transistors (HEMTs) are measured using gate metal resistance thermometry (GMRT). The technique characterizes the thermal response of device gate metallization to determine the gate-epilayer junction temperature (Tj), which is directly influenced by the channel heat source due to its close proximity. It is found that low gate leakage levels in GaN HEMTs make them favorable candidates for GMRT. Bias-dependent self-heating, independent of power dissipation, is observed in the devices. Therefore, Tj of different device configurations are compared at constant bias state, as well as constant power density (3.75 W/mm) to improve accuracy. Tj reduction is observed at high drain bias due to the migration of the channel heat source toward the gate field plate edge. This provides independent experimental validation for a reported electrothermal model [7]. A 3-D thermal finite element method model is presented, which simulates measured Tj rise to within ~6% across a range of device configurations and operating conditions. This is ultimately made possible upon implementation of a thermal boundary resistance layer and extraction of its temperature response using GMRT data.

Gate junction temperature is presented as the crucial parameter for modeling thermal degradation in GaAs device reliability studies, and sufficient for modeling the impact of temperature on device terminal characteristics. Gate metal resistance thermometry (GMRT) is applied to a GaAs pseudomorphic high-electron mobility transistor to measure its gate junction temperature. It is found that gate leakage current due to impact ionization can interfere with dc GMRT measurements. To the best of our knowledge, for the first time it is demonstrated that this can be largely avoided by instead applying an ac version of GMRT. However, the dynamic resistance of the gate leakage current path can interfere with ac GMRT. Measurements and thermal finite element method simulations of devices at constant power dissipation conclude that the bias dependence of the channel heat source profile affects the gate junction temperature. A parameter extraction technique is presented and used in device lifetime calculations to demonstrate MTTF variations of more than an order of magnitude (despite fixed power) due to bias-dependent self-heating.

The frequency range 25–45 GHz contains point-to-point bands at 28, 32, 38 and 42 GHz, potential implementation of 5G at 28 and 39 GHz and various military applications. Traditionally, short gate length GaAs pHEMT technology has been used to develop products for these frequencies. Alternatively, SiGe HBT technology may offer lower cost solutions for systems that can tolerate lower performance. This paper presents the design and measurements of a broadband SiGe receiver with a noise figure of 6 ± 1 dB over the entire 25 to 45 GHz bandwidth. The measured gain exceeds 20 dB from 26 to 43 GHz and, with gain control, is sufficiently linear to support 1024 QAM in the 35 to 45 GHz range. To the authors' knowledge, this the broadest bandwidth achieved to date with a SiGe receiver at these Ka or low millimetre-wave frequencies.

150 GHz amplifiers fabricated on a commercial GaAs process with an f T of 135 GHz are presented. The core design achieves a gain of 10 dB or more from 105 to 150 GHz and the balanced variant has a bandwidth of 100 to 150 GHz and output power above 8 dBm at 140 GHz. Significantly, this coplanar design was carried out with a model extracted from biased S-parameters up to only 50 GHz taken on a microstrip device with different gate width. The measured S-parameters and output power of the amplifiers agree remarkably well with that predicted by the model.

An accurate scalable 3-D thermal finite-element-method (FEM) model is developed and verified for a GaAs pHEMT process using gate resistance thermometry (GRT) as the basis. The measurement technique is suited to scalable model development, since the gate metal is in intimate proximity to the heat source in the device channel. The FEM model is demonstrated to scale with channel power dissipation and gate periphery, simultaneously. Agreement to within 6% of all measured configurations/operating conditions is demonstrated. The model is suitable for inclusion in semiconductor foundry design kits to determine thermal resistance values for nonlinear device models, and also for thermal analyses of power amplifier layouts.

Modern microwave circuit performance is susceptible to dispersion of the characteristics of microwave FETs. This is because the complex signals used in communication systems invoke charge trapping and self-heating mechanisms. These mechanisms are sensitive to bias, temperature, and frequency variations. A major difficulty in characterizing charge trapping in microwave FETs is to differentiate between the self-heating and charge trapping rates. In this paper, the trapping behavior in a GaN HEMT is characterized by performing isothermal three-stage pulse measurements.

A 3D printed dual ridged horn antenna (DRHA) is presented. The antenna design is optimized for additive manufacturing and is 3D printed using acrylonitrile butadiene styrene (ABS) and then painted with nickel based aerosol spray. The coaxial transition is also included in the 3D printed prototype. The antenna was manufactured with the intention of improving learning and education of electromagnetism and antennas for undergraduate students using a low cost personal desktop 3D printer. The painted DRHA has a 10 dB return-loss bandwidth of 6621 MHz (1905 MHz–8526 MHz) with a peak gain of 11 dBi. This prototype is the first known ABS based horn antenna with the coaxial transition embedded into it.

© 2016 IEEE. Personnel detection embedded in foliage is extremely important to border patrol, perimeter protection and search-and-rescue operations. In this paper, we explore the utility of radio-sensor network (RSN) to distinguish between humans and animals. We explore the phenomenon that signals are always affected by the presence of obstacles and identify human based on the received signals by transceivers, which leads to a potential low-cost way for personnel detection without specific sensors. In our study, the impulse radio ultra-wideband (IR-UWB) technology is selected for the RF transceiver due to the fact that it is not only energy efficient, but also robust against interferences. The principle component analysis (PCA) is applied to extract the feature vector, and a support vector machine is used as the target classifier. Experiment result with an average accuracy of 97.5% based on actual data collected in a cornfield indicates that this approach has a good capability to distinguish between human and animals in a foliage environment.

© 2016 IEEE. An ultra-compact integrated resonator and bandpass filters (BPF), in silicon-based technology, are presented for millimetre-wave applications. The resonator consists of two broadside-coupled lines in opposite orientations. Using this resonator, a first-order and a second-order BPFs were also designed. To prove the concept, three prototypes of each of the resonator and the first-order BPF were fabricated using a standard 0.13-μm SiGe process. The measured results show that the resonator has an attenuation of 13.7 dB at the resonance frequency of 57 GHz, while the BPF has a centre frequency of 31 GHz and an insertion loss of only 2.4 dB. Excluding the pads, the chip size of both the resonator and the BPF is extremely compact, only 0.024 mm2 that is equivalent to 0.001 λg2. The unloaded Q factor of the filter is higher than other state-of-the-art designs.

The development of transient gate resistance thermometry (T-GRT) is reported. It is a technique used to measure the transient self-heating of a FET's gate metal. Demonstrations of T-GRT are presented at the wafer level on a GaAs pHEMT and an AlGaN/GaN-on-SiC HEMT. Dynamic self heating is monitored from hundreds of nanoseconds to hundreds of milliseconds. Preliminary finite-element simulations across a range of power dissipation levels agree closely with T-GRT at, and beyond, 1 µs after the applied drain pulse. Characterization of dynamic self heating and its application to pulsed applications such as radar are discussed.

This paper reports the investigation of RF GaN HEMTs as integrated power switches in high frequency, high efficiency switching topologies. GaN HEMTs suffer from trap phenomena which degrades the performance of the HEMT when used as power switches. Pulsed IV characterisation revealed upto 50% reduction in the theoretically available output power, at pulse frequency of 500 KHz and quiescent switch voltage of 60V. Transient measurements done a MMIC switching circuit with integrated drivers fabricated in the same process delivered an output power of 5.8 W at a switching frequency of 100 MHz and drain voltage of 30V.

Novel and realistic application of hot-via interconnects to millimeter-wave active and power MMICs is demonstrated for the first time. Power amplifier MMICs in the 80- and 100-GHz range were successfully designed, assembled, and characterized for wire-bond free chip interconnect technology. With hot-via RF transitions, compact E-band power amplifier MMICs directly soldered onto evaluation boards demonstrate 22-dB gain and over 28-dBm output power in the ETSI band of 81–86 GHz, with little performance degradation compared to reference circuits probed with traditional front-side RF pads. Similarly, a broadband amplifier, when interconnected to its matching PCB, delivers 13-dB of gain in the W-band, and 21-dBm P1dB. To the author's knowledge, this work represents the highest frequency demonstration of any soldered millimeter-wave hot-via active circuits onto standard PCBs, with remarkable measured power performance, closely equaling that of ideally front-side RF probed PA MMICs.

A compact slotted planar inverted-F antenna (PIFA) with a superstrate is presented in this paper. The proposed antenna covers 28 GHz millimeter wave frequency bands and can be useful for future 5G hand held devices. The antenna has been designed to be integrated to a mobile phone substrate of dimensions 110 mm × 60 mm, while reserving 70 mm × 35 mm area for a battery, and occupies a small volume of 4 mm × 4 mm × 1.34 mm. It has a wide operating bandwidth (|S11| < − 10dB) of 3.18 GHz (27.57–30.75 GHz) and a peak gain of 8.8 dBi with a gain variation of less than 0.83 dB within the operating bandwidth. The proposed antenna has stable broadside radiation in yz and xz planes with low side lobe levels. It features wide half power beamwidths of 65.90 in the xz plane and 61.10 in the yz plane at 28 GHz. Radiation efficiency and total efficiency of the antenna vary between 97.9%–98.8% and 69.3%–97.3%, respectively.

© 2015 IEEE. Sensitivity analysis plays an important role in a variety of statistical methodologies, design procedures and model selection. For development of in-body wireless communications, it is essential to evaluate the designed system performance prior to conducting any practical procedures. Localization of a capsule endoscope inside the gastrointestinal tract is one of the areas that needs to be precisely addressed in wireless body area networks. Since practical experiments on the real human body are quite infeasible, various human phantom models have been developed for this purpose. This study provides a detailed sensitivity analysis for two different anatomical human phantom models. The study shows that the adjustment of best possible grid and the number of cells have a significant impact on the simulation results to obtain a precise path loss and consequently to estimate an accurate location of capsule. This all aid us to improve the system performance.

A compact planar inverted-F antenna (PIFA) with single layer dielectric load is presented in this paper. The proposed antenna covers 28 GHz millimeter wave frequency bands and can be useful for future 5G hand held devices. The antenna is placed on a mobile phone substrate of dimensions 110 mm × 60 mm reserving 70 mm × 35 mm for a battery, and occupies a small volume of 4 mm × 4 mm × 1.34 mm. The antenna has a wide operating bandwidth (|S11| < −10dB) of 980 MHz (27.47 – 28.45 GHz) and a peak gain of 8.80 dBi with a gain variation of less than 0.55 dB within the antenna bandwidth. The proposed antenna has stable broadside radiation in yz and xz planes with low side lobe levels of −13.3 dB, −14.4 dB, and wide beamwidths of 66.6°, 64.5°, respectively. Radiation efficiency and total efficiency of the antenna vary between 97% – 99% and 88% – 96%, respectively. Antennas impedance bandwidth, gain, radiation, and total efficiency are assessed with and without a battery.

A difficulty concerning characterization of charge trapping in microwave FETs by performing pulse measurements is the possible overlap between the trapping and self-heating rates. Another difficulty is that the potential introduced by charge trapping modulates the drain-source current differently at bias points with different values of drain-source conductance, gm, and drain transconductance, g d . Measurement of true-DC values for g m and g d at all bias points will then be required for estimating the potential introduced by charge trapping. For devices such as GaN HEMTs, true-DC values for gm and g d at each bias point can be obtained only after thousands or tens of thousands of seconds after pulsing the device. A new pulse-measurement technique is proposed that overcomes these difficulties. The results of measurements performed on a GaN HEMT using the proposed pulse-measurement technique is presented, and the observed trapping behavior is characterized.

© 2016 IEEE. A compact transformer balun with less than 0.13 dB magnitude imbalance and 0.4° phase imbalance from 7 to 15 GHz is presented. The balun is suitable for use with frequency doublers using a balanced circuit architecture. Measured data for the balun is used to predict the harmonic rejection of the frequency doubler. The fundamental rejection is 29 dB and third harmonic rejection is better than 35 dB. The balun is 420 μm by 320 μm.

A 1.5 V 4.5 mW 3-5 GHz low-noise amplifier (LNA) suitable for power-constraint application is implemented in a 0.25-μm silicon-on-insulator CMOS process.The designed LNA with good input and output impedance matching exhibits gain of 10.3 dB and 2-2.9 dB noise figure within the 3-5 GHz band. Moreover, the -3 dB bandwidth of the presented LNA is insensitive to process corner variations. A third-order input intercept point of -5 dBm is also achieved for the LNA at 3.6 GHz. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:89-93, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27262 Copyright © 2012 Wiley Periodicals, Inc.

The integrated design flow that links simulation, layout, and electromagnetic (EM) analysis is the foundation for modern RF/microwave integrated circuit (IC) design. The inclusion of thermal simulation in this flow is now possible with modern thermal solvers linked into RF/microwave integrated design tools. Silicon germanium (SiGe) heterojunction bipolar transistor (HBT) power amplifier (PA) design is used as an example where such a flow is most beneficial due to numerous issues such as array sizing and thermal runaway. An electrothermal flow is discussed relative to some overall metrics for design flows and that incorporates the availability of an integrated thermal solver into the earliest parts of, and potentially throughout, the entire design flow. The result is a flow that potentially reduces iterations during the design process and boosts design performance by freeing up margin.

This paper presents a low power, low drop-out (LDO) voltage regulator, designed and implemented using 0.18 micron CMOS process. With a supply voltage of 1.8V, 50mA current and with a single compensation capacitor of 1pF. A constant transconductance current reference is used as a bias circuit for the Error Amplifier. The maximum output load current is 50mA at a regulated output voltage of 1.68V.The voltage regulator delivers a full load transient response of 5.5mV overshoot and 3.4mV undershoot. Furthermore, the LDO PSRR rating is −73dB @ 16.7MHz, and a relatively low power of 90mW.

In summary, nonlinear modeling is not a trivial exercise: it is our version of rocket science. Compact models have served us well for many years, but there are several shortcomings that behavioral models can address. The industry is experiencing some very heady times for measurement-based models and the test and measurement systems needed to gener ate them. Great progress has been made, but more experience will be needed with measurement-based models before the caveat emptor-let the buyer beware-is completely understood. For this to be accelerated, measurement-based model use and mis use needs to be communicated in a timely manner in a format and within a forum where the collective effort can be freely, openly, and easily discussed with minimal ambiguity. The OWF is working to address this. Like S-parameters before, there will be an adoption period, but if measurement-based mod els live up to their promise, there are very exciting days ahead indeed.

Different placement strategies for Field-Effect-Transistor (FET) active switching devices in an electromagnetic band gap (EBG) periodic structure are investigated. Two possible placements for the switches are considered: (a) switches on top of a substrate and (b) switches at the ground-plane level. Their advantages and drawbacks are analyzed and discussed in relation to fabrication, extension to 2-D and ground plane design. The transmission results and band gaps of the EBG structure are presented for both switch placements. When determining the transmission of the structure, the FET switches are modeled in two different ways, first as an ideal conductor and then using a more accurate model consisting of embedded scattering parameters. Significant differences have been observed between the results predicted using simple and accurate models. Experimental characterization of the switch reveals technological issues related to their biasing.

Sensitivity analysis plays an important role in a variety of statistical methodologies, design procedures and model selection. For development of in-body wireless communications, it is essential to evaluate the designed system performance prior to conducting any practical procedures. Localization of a capsule endoscope inside the gastrointestinal tract is one of the areas that needs to be precisely addressed in wireless body area networks. A highly accurate location estimation of a capsule endoscope in the range of several millimeters is a challenging task. This is mainly because the Radio-Frequency signals encounter a high loss and a highly dynamic channel propagation environment. Therefore, investigation of an accurate path-loss model is required for the development of localization algorithms. Since practical experiments on the real human body are quite infeasible, various human phantom models have been developed for this purpose. This study provides a detailed sensitivity analysis for two different anatomical human phantom models and shows how much the adjustment of the voxeling and the number of cells in phantom models are crucial to reduce the measurement errors in path loss and improve system performance.

A digitally controlled half-width microstrip leaky-wave antenna (LWA) is presented for fixed-frequency beam scanning. The free edge of a half-width microstrip line is loaded with a number of periodic interdigital capacitors. Each capacitor is connected to the ground plane by a digital switch. By dynamically changing the reactance profile at the free edge of the microstrip the beam direction is changed at a fixed frequency. Full-wave numerical simulations show that the antenna has the ability to scan the main beam from 35° to 56 ° at 5.75 GHz. Refereed/Peer-reviewed