X-band Power Research Articles

X-Band Power Divider Design and Its Network for Active Electronically Scanned Array Vertical Integration

X-Band Power Divider Design and Its Network for Active Electronically Scanned Array Vertical Integration

Corrections to “High Power X-band Monolithic GaAs PIN Balanced Limiter” [Apr 23 4623-4631

Corrections to “High Power X-band Monolithic GaAs PIN Balanced Limiter” [Apr 23 4623-4631

Nonlinear Properties of an Inhomogeneous Diode Structure in a Strong Microwave Field

Results of experimental investigation of detection (rectification) of high power X-band microwave signal in diodes of various design (semiconductor p-n-junction, point-contact, Schottky, Metal-Isolator-Metal—MIM) are reported. The maximum of the detected direct voltage V vs. power P of microwave signal and subsequent polarity reversal, previously found in MIM diodes in the optical and microwave bands, have found to be characteristic of all investigated diodes as well. After the reversal of polarity, this dependence comes linear, and the sign of the voltage corresponds to thermoEMF. In some diodes, the hysteresis on V(P) was observed. All 5 types of V(P) of MIM diodes (have made from different pairs of metals), reported earlier, were reproduced on same p-n-junction diode by variable external DC bias. These results joined with abnormal frequency cutoff forced to suggest that there is an unknown mechanism for direct flow of charge carriers (and for generate direct current) in the high-frequency electrical field, which differs from the conventional rectification.

Coplanar Asymmetry Transformer Distributed Modeling for X-Band Drive Power Amplifier Design on GaN Process

In this paper, a methodology for designing a distributed model for coplanar asymmetry transformer on gallium nitride (GaN) process is proposed, which can accurately characterize the transformer’s feature up to a millimeter-wave band. The paper analyses a transformer-based matching circuit and proposes a practical transformer design procedure. A two stage, transformer matching based X-band power amplifier (PA) is reported here. Using the proposed transformer model and correlated transformer design procedure can sharply reduce schematic design period and optimum process time. The PA chip is designed on a 0.25 µm GaN technology process and occupies a 1.515 mm2 area. At a 28 V supply, the gain and output power of the PA reaches 15 dB and 29 dBm respectively, and the wideband matching transformer reaches 47.6% bandwidth. To the best of our knowledge, the distributed model for coplanar asymmetry transformer and transformer-based X-band MMIC PA on GaN process in this work is the first case among the reported papers.

Design and Fabrication of a High-Efficiency and High-Gain X-Band Power Amplifier Using GaN-HEMT Die Transistors for Satellite Communications

Design and Fabrication of a High-Efficiency and High-Gain X-Band Power Amplifier Using GaN-HEMT Die Transistors for Satellite Communications

Fast electromagnetic analysis of an X-band power injection coupler of dielectric-loaded accelerator using a novel transmission line model

In this paper, a novel transmission line model of a dielectric-loaded waveguide is introduced and employed to analyze a non-uniform dielectric-loaded coupler. In this method, a dielectric-loaded waveguide is equaled by a fully dielectric-filled waveguide with the same phase constant, power flow, and dissipated powers in the dielectric part and wall of the waveguide. This leads to a set of four non-linear equations. Four unknown variables of the filled-waveguide including the real and imaginary parts of dielectric permittivity, inner radius, and conductivity of the metal body of the waveguide can be obtained by solving the equation system. To investigate the validity of the new model, an X-band tapered dielectric-loaded coupler is considered and its scattering matrix parameters are obtained by a full-wave electromagnetic (EM) software. By segmentation of the coupler structure into a large number of uniform dielectric-loaded tubes and using the proposed transmission line model for every section, the whole structure can be considered as a series of transmission lines. Then, by calculating the total transmission matrix of the coupler, the scattering matrix parameters are achieved. It is shown that there is an acceptable agreement between the total behavior of the analytical and simulation results. Moreover, the fast proposed method with a combination of optimization algorithms can provide an initial point of design for further more accurate full-wave optimizations to reduce the total time of the optimization process.

A Two-Stage X-Band 20.7-dBm Power Amplifier in 40-nm CMOS Technology

For higher integration density, X-band power amplifiers (PAs) with CMOS technology have been widely discussed in recent publications. However, with reduced power supply voltage and device size, it is a great challenge to design a compact PA with high output power and power-added efficiency (PAE). In the proposed design, a 40-nm standard CMOS process is used for higher integration with other RF building blocks, compared with other CMOS PA designs with larger process node. Transistor cells are designed with neutralization capacitors to increase stability and gain performance of the PA. As a trade-off among gain, output power, and PAE, the transistor cells in driving stage and power stage are biased for class A and class AB operation, respectively. Both transistor cells consist of two transistors working in differential mode. Furthermore, transformer-based matching networks (TMNs) are used to realize a two-stage X-band CMOS PA with compact size. The PA achieves an effective conductivity (EC) of 117.5, which is among the highest in recently reported X-band PAs in CMOS technology. The PA also attains a saturated output power (Psat) of 20.7 dBm, a peak PAE of 22.4%, and a gain of 25.6 dB at the center frequency of 10 GHz under a 1 V supply in 40-nm CMOS.

Design and fabrication of an eight-port binary Wilkinson power splitter

An eight-port X-band power splitter based on binary Wilkinson power splitter topology is presented in this paper. The proposed power splitter consists of three stages, with one, two, and four equal power splitters in the first, second, and third stages, respectively. The input power is divided equally between the eight outputs to provide an equal-split power splitter. Evaluation of the structure is carried out using even- and odd-mode techniques. An epoxy laminate FR4 substrate with thickness of 0.5 mm is chosen, while the designed power splitter is simulated using Keysight Advanced Design System 2019 and ANSYS High Frequency Structure Simulation. As the results indicate, excellent performance is obtained for the power splitter, with a reflection coefficient of -36.5 dB and an insertion loss of -9.32 dB at the 9.65 GHz center frequency. The proposed power splitter has the potential to be employed in radar and microwave systems, specifically in phased-array structures.

High linearity and high power performance with barrier layer of sandwich structure and Al0.05GaN back barrier for X-band application

The high power and linearity performance of GaN-based HEMT for X-band application was achieved using the barrier layer of sandwich structure and Al0.05GaN back barrier. The AlGaN-sandwich-barrier can modulate polarization-graded field for more flat transconductance profile under the high drain bias. Only about 7.5% current collapse (CC) occurs for drain quiescent bias of 40 V. Due to the Al0.05GaN back barrier, the three-terminal off-state breakdown voltage (BVDS) of 260 V and a very small drain-induced barrier lowering (DIBL) of 2.7 mV V−1 is achieved. The AlGaN sandwich barrier combined with Al0.05GaN back barrier device exhibits a high current-gain cutoff frequency f T of 42 GHz@VDS = 10 V, and a high power-gain cutoff frequency f MAX of 130 GHz@VDS = 60 V. Load-pull measurement at 10 GHz revealed a saturated power density of 7.3 W mm−1 was achieved with an associated PAE of 29.2% and Gain of 10.6 dB. Two-tone measurement at 10 GHz showed an OIP3 of 38 dBm and a corresponding linearity figure-of-merit OIP3/PDC of 4.5 dB. These results demonstrate the great potential of AlGaN-sandwich -barrier/GaN/Al0.05GaN HEMTs as a very promising alternative to high power and high linearity X-band power amplifier.

Realization of a broadband hybrid X-band power amplifier based on fT-doubler technique

This paper presents the design steps for the fabrication of a hybrid microwave power amplifier (PA) based on fT-doubler technique. The PA is implemented using two 6 W discrete GaN-HEMTs on SiC substrate. The fT-doubler technique is used to enhance the frequency response and bandwidth of the PA as compared to the common source (CS) configuration. Accurate simulation results show about 90% improvement in the unity current gain frequency (fT) for the fT-doubler structure in comparison with a common-source parallel structure. However, the hybrid realization of a high-frequency PA based on fT-doubler technique is challenging mainly due to severe thermal management failures and large parasitic effects of the interconnections such as bond wires and long microstrip lines. The proposed hybrid integrated strategy relieves the thermal problem while the parasitic effects are well controlled. Thermal analysis and accurate 3D thermal simulation of the proposed hybrid integrated structure show that the channel temperature of transistors does not exceed its maximum tolerable value. Implementing the optimal source/load pulls for the transistors and well-designing the input/output matching networks by considering the parasitic effects of the interconnections result in a fabricated PA with a broad bandwidth of 6.5–10.4 GHz, a sufficient small-signal gain of 10 dB, a considerably high output power (Pout) of around 10 W and a power added efficiency (PAE) of 43% at 8 GHz.

A 20.5-dBm <inline-formula> <tex-math notation="LaTeX">$X$ </tex-math> </inline-formula>-Band Power Amplifier With a 1.2-V Supply in 65-nm CMOS Technology

In this letter, we present an X-band power amplifier (PA) which achieves a saturated output power ( $P_{\mathrm {sat}}$ ) of 20.5 dBm under a 1.2-V supply in 65-nm CMOS. Considering the relatively low breakdown voltage of the 65-nm device, we adopted a differential configuration with a triple-well cascode in which the n-well of the cascode device was biased with a resistor. Also, the PA adopted an on-chip 1:2 transformer to provide a low output impedance at the drain, and a series RC feedback was employed to enhance the stability and the gain bandwidth (BW) as well. The measured 3-dB BW of the PA covered the whole X-band and supported an output 1-dB gain compression point (OP1dB) of 15.2 dBm. A peak power-added efficiency of 24.6% with a gain of 24.4 dB at 9 GHz was recorded. The core of the PA occupies only 0.48 mm2.

Development of X-Band Transceiver MMIC’s Using GaN Technology

This paper describes X-Band power amplifier (PA), low noise amplifier (LNA) and switches that can be used in transmit/receive modules which are developed with GaN technology. For Transmit chain two 25 W high power amplifiers that are tuned between 8-10 GHz and 10-12 GHz bands are designed. A low noise amplifier with 2 W survivability and less than 2dB noise figure is designed for receive chain Furthermore, an RF switch that is capable of withstanding 25 W RF power is developed for the selection of transmit or receive chains. Measurement results show that both power amplifiers produce 25 W of power. Low noise amplifier has more than 20 dB small signal gain with less than 2 dB noise figure. RF switch has 50 dB of isolation with less than 1 dB insertion loss.

On the new prospects of high power wideband TWT creation

A new design of a slow - wave structure of a “crossed staircase” type for a powerful broadband multi-beam X-band TWT has been considered. The use of dense packing of beams and diaphragms with bushings allows to increase the interaction impedance to 4-7 Ohm and the dispersion correction makes it possible to expand the band up to 18% using a special form of coupling slots. The calculation of electronics demonstrates a possibility of obtaining the power of 24 kW, gain of 17 dB and efficiency of 28% in the TWT with such a slow-wave structure. The design of the permanent magnet system with an interpole gap of 119 mm was developed which provides 100% transportation of the electron beam to the collector.

X-Band Power and Linearity Performance of Compositionally Graded AlGaN Channel Transistors

We report on the power and linearity performance of metal organic chemical vapor deposition grown AlGaN channel polarization-graded field-effect transistor (PolFET). The fabricated transistors with 3-D electron channels showed nearly flat transconductanceprofiles. Maximum f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> and fmax of 23 and 65 GHz were measured for 0.7-μm gate-length transistors, corresponding to an f <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</sub> -L <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G</sub> product of 16.2 GHz·μm. Load-pull measurement at 10 GHz revealed a maximum output power of 2 W/mm with a maximum small signal gain of 16 dB. Two-tone measurement at 10 GHz showed an OIP3 of 33 dBm for 150-μm device width and a corresponding linearity figure-of-merit OIP3/PDC of 3.4 dB. These results suggest that PolFETs could be useful for high-frequency applications requiring high linearity.

A Two-Stage &lt;inline-formula&gt; &lt;tex-math notation="LaTeX"&gt;$S-/X$ &lt;/tex-math&gt; &lt;/inline-formula&gt;-Band CMOS Power Amplifier for High-Resolution Radar Transceivers

This paper presents a reconfigurable S-/X-band power amplifier (PA) integrated into a 0.18-μm RF CMOS process. A switchable transformer for output matching is operated by tuning its primary winding and a shunt capacitor under a 50-Ω load with passive efficiency of more than 63%/67% for the S-/X-band. Series resonant circuits with bond wires are employed at common-mode nodes, greatly improving the X-band performance of the PA. Despite the use of interstage matching without any tunable elements, the PA presents a power gain of more than 19.5 dB at both 3 and 8 GHz. The PA provides saturated output power of 24.8/21.5 (21.5) dBm with a power-added efficiency of 32.8%/11.1% (10.7%) at 3/8 (9) GHz. The 1-dB bandwidth is 0.6/2 GHz (2.8-3.4/7.5-9.5 GHz) for the S-/X-band. This amplifier demonstrates suitable performance for dual-band high-resolution radar transceivers.

The interaction of intense, ultra-short microwave beams with the plasma generated by gas ionization

Results of the non-linear interaction of an extremely short (0.6 ns) high power (∼500 MW) X-band focused microwave beam with the plasma generated by gas ionization are presented. Within certain gas pressure ranges, specific to the gas type, the plasma density is considerably lower around the microwave beam axis than at its periphery, thus forming guiding channel through which the beam self-focuses. Outside these pressure ranges, either diffuse or streamer-like plasma is observed. We also observe high energy electrons (∼15 keV), accelerated by the very high-power microwaves. A simplified analytical model of this complicated dynamical system and particle-in-cell numerical simulations confirm the experimental results.

Ultra‐low‐LO‐power X‐band down‐conversion ring mixer using weak‐inversion biasing technique

An ultra-low-LO (local oscillator)-power X-band down-conversion ring mixer in 0.18-μm CMOS process is presented. By using the weak-inversion biasing technique, the proposed X-band ring mixer exhibits low-dc-power consumption and low-LO-drive power while maintaining a reasonable conversion gain (CG). The measurement results show that the proposed mixer demonstrates a maximum CG of 1.75 dB with ultra-low-LO-power of −8 dBm at RF of 12 GHz and IF of 100 MHz. The dc power is only 2 mW. The 3-dB RF bandwidth is from 9 to 15 GHz and the output 1-dB compression point (OP1 dB) is −14 dBm.

$X$ -band DC–DC Power Converter for High-Speed Bit-Stream Modulation

This letter proposes an X-band power converter for high-speed bit-stream modulation. The converter consists of a power amplifier (PA) with pulsed load modulation, which performs highly efficient dc–ac conversion for a wide range of output powers, and a switching rectifier. Power conversion was performed in the X-band, and the potential for broad bandwidth and profile minimization was demonstrated. The PA was fabricated using a discrete gallium-nitride HEMT device and it delivered 39-dBm RF output power with 57.4% drain efficiency (DE) at 9.2 GHz under class-B conditions. At 6-dB output power back-off, 38.2% DE was measured for a 4 Gb/s data rate. The switching rectifier is designed using a class-B PA strategy to demonstrate the proposed concept. The ac–dc conversion efficiency was measured to be 44.6%, and 3.05-W dc power was delivered.

X-band power amplifier for next generation networks based on mesfet

Advanced wireless standards of communication like 3GPP and LTE are becoming more and more efficient and with this evolution of communication systems mobile equipment is also become smaller and smaller. Power amplifier designing has become a very crucial task in this era where efficiency and size are the main concern of any designer. In this paper we have design and analyzed X-band Class E Metal-semiconductor field effect transistor (MESFET) based Power Amplifier. This device targets the devices which use OFDM technique to improve their spectral efficiency for the next generation communication systems. Microstrip lines are used to achieve small size for our design instead of lumped components. Load Pull measurements are used to get MESFET input and output impedances optimum values. For linear and non linear operation small signal mathematical model of the design is used. To reduce thermal losses FR4 substrate is used to increase PA efficiency. Our designs shows small values of input and output return loss of about -22.3dB and -23.716 dB achieving a high gain of about 25.6 dB respectively, with PAE of about 30 % having stability factor greater than 1 and 21.894dBm of output power

A Compact 60W X-Band GaN HEMT Power Amplifier MMIC

The design and performance of a compact X-band power amplifier MMIC utilizing Nanjing Electronic Devices Institute’s (NEDI’s) $0.25~\mu \text {m}$ gallium nitride (GaN) high electron mobility transistor (HEMT) technology is presented. The MMIC operates in pulse conditions with typical pulse width of $100~\mu $ sec and 10% duty cycle. An output power of 47.5 dBm to 48.7 dBm with over 20 dB power gain and a power added efficiency (PAE) of 40% to 45% over the band of 8-12 GHz under a drain voltage of 28 V have been achieved. The chip size is $3.5\times 3.8$ mm2 and the amplifier delivers an output power density up to 5.57 W/mm2 over the chip area and up to 6.43 W/mm over the active periphery of the power stage. The thermal resistance is 1.7 °C/W measured in CW mode.