Decade Bandwidth Research Articles

Design of a Compact GaN Power Amplifier With High Efficiency and Beyond Decade Bandwidth

This letter presents a power amplifier (PA) design and network synthesis approach to achieve wideband and efficient performance with a very compact circuit size. A design method is presented in detail to convert a canonical filter-based high-order matching network to the proposed matching configuration with transistor parasitic and packaged elements absorption, and a compact passive network footprint. As a proof of concept, a prototype GaN HEMT PA is implemented. Starting from a fourth-order output network filter, the inductances and capacitance of the filter elements are re-organized to model, and thus absorb the output parasitics of the transistor, leading to a compact footprint with only four transmission lines. The measured results show that the prototype PA achieves an output power of 41.9–44.3 dBm and a 55%–74% drain efficiency, over a record-high decade bandwidth (0.35–3.55 GHz).

An active,ultra‐wideband dual‐polarizedtightly coupled dipole subarray for satellite communication

How to integrate the tightly coupled dipole array (TCDA) with tile-based power combination network (PCN) has never been discussed in literatures. However, it is a critical issue should be resolved for TCDA's compact design. This article investigates a crucial front-end component—8 × 8 dual-polarized tightly coupled dipole subarray (TCDSA)—for ultra-wideband satellite communication (SATCOM). A tile-based network architecture is proposed to realize a low-volume active PCN for the TCDSA. Then, a vertical interconnection module is proposed to totally eliminate coaxial cables between antenna elements and the PCN. A prototype of the TCDSA is developed. The PCN is elaborately integrated with the antenna elements in a compact space within a total thickness of 2.0 cm. The overall height of the prototype is 206.6 mm (2.07λH), where λH is the wavelength at the high-end operating frequency. The fabricated dual-polarized prototype demonstrates a decade bandwidth of 0.3–3.0 GHz with low cross-polarization levels (<−30.0 dB). Because of the compact structure and excellent performance, the developed TCDSA will find applications in future receiving systems for SATCOM.

Increase the bandwidth of the power amplifier to 185% of the bandwidth by ferrite transformers

ABSTRACT The motivation of this paper increases the bandwidth of power amplifier to multioctave by matching circuit, which consists of ferrite balun, 4:1 transformers and RC network feedback to make atrade-off between gain and VSWR. So this work discusses the design of a push-pull power amplifier demonstrating over more than a decade bandwidth using matching networks to achieve [30–800] MHz bandwidth. Matching transformer techniques can be used in order to minimise the return loss and increase the gain. Modification of the classical topology, based on inductive compensation of the parasitic capacitance of ferrite, has been proposed and used to design a 1:4 transformer. Practically, miss-match and heating is the main concern for broadband performance of high power amplifier. Coaxial cable and ferrite are also used to dissipate the heat (high temperature) resulting from the amplification power, in addition to installing the board on a cooler with appropriate dimensions, so we get the best match and stability. The simulation results are compared with the measurements. The measured results show that 20.5–17.46 dB of gain, 50.5–47.46 dBm of output power, and 50.9 of drain efficiency are delivered.

Dielectrically Loaded Quad-Ridge Flared Horn for Beamwidth Control Over Decade Bandwidth—Optimization, Manufacture, and Measurement

We present the design, manufacture, and measured performance of a dielectrically loaded quad-ridge flared horn (QRFH) feed for decade bandwidth radio astronomy application. The introduction of the dielectric load improves the QRFH beamwidth control in H-plane at the mid and upper frequency range. Consequently on the reflector, illumination efficiency, phase efficiency, and the intrinsic cross-polarization ratio (IXR) have been improved. The dielectric load is made from homogeneous low-loss polytetrafluoroethylene and has a low profile with a cylinder shape for simple installation at the center of the QRFH. The dielectrically loaded QRFH presented here covers 1.5–15.5 GHz with a calculated average aperture efficiency above 50% on a f/D = 0.3 prime-focus reflector. We present a calculation of system noise temperature and sensitivity for the QRFH on a 100 m prime-focus reflector. Measured beam patterns of the QRFH are in good agreement with the simulations over the full frequency band. The input reflection coefficient was predicted to be below −10 dB across the bandwidth. We present a tolerance analysis that explains why the measured one deviates.

Super‐wideband CPW fed modified square monopole antenna with stabilized radiation characteristics

AbstractThis article explores the design and analysis of a CPW fed modified square monopole antenna for super wideband (SWB) application. Three key features of proposed radiating structure are: (1) semi‐circular base provides smother impedance variation and helpful in the creation of more than decade (10:1) impedance bandwidth (super‐wideband); (2) modified square shaped monopole reduce the lower frequency of operation and create larger BDR value (7871.49); (3) trimmed edges provide stabilized radiation characteristics even at higher frequencies. In order to endorse the simulated outcomes, prototype of proposed antenna structure is fabricated and tested. Good settlement is to be found between measured and simulated outcomes. From experimental results, it confirms that the proposed radiator is operating over more than decade (14.52:1) bandwidth that is, 0.95‐13.8 GHz (VSWR &lt; 2). Time domain analysis of proposed radiator also supports its applicability for SWB applications. The proposed radiator is quite appropriate for different wireless applications such as Amature Radio, Digital Audio Broadcasting, ISM, Wi‐Fi, GPS, Bluetooth, WLAN, and UWB applications.

A Decade-Bandwidth Distributed Power Amplifier MMIC Using 0.25 μm GaN HEMT Technology

This study presents a 2–20 GHz monolithic distributed power amplifier (DPA) using a 0.25 μm AlGaN/GaN on SiC high electron mobility transistor (HEMT) technology. The gate width of the HEMT was selected after considering the input capacitance of the unit cell that guarantees decade bandwidth. To achieve high output power using small transistors, a 12-stage DPA was designed with a nonuniform drain line impedance to provide optimal output power matching. The maximum operating frequency of the proposed DPA is above 20 GHz, which is higher than those of other DPAs manufactured with the same gate-length process. The measured output power and power-added efficiency of the DPA monolithic microwave integrated circuit (MMIC) are 35.3–38.6 dBm and 11.4%–31%, respectively, for 2–20 GHz. Keywords: Decade Bandwidth, Distributed Power Amplifier, High Power Amplifier, MMIC, 0.25 μm AlGaN/GaN HEMT

Broadband and thin magnetic absorber with non-Foster metasurface for admittance matching

One of the long-standing and challenging problems in microwave engineering is the realization of ultra-wideband absorption using extremely-thin structures. Magnetic material can facilitate thickness reduction for microwave absorbers but also bring inherent narrowband admittance matching conundrum originating from its frequency-dispersive permeability and high permittivity. In this paper, we propose a simple and yet effective solution based on the concept of admittance matching with non-Foster metasurface (NFMS). Building on this concept, an ultra-wideband and extremely-thin magnetic absorber is achieved, with a simple structure consisting of a conductor-backed magnetic sheet (CMBS) coated by a NFMS. The NFMS with negatively inductive susceptance can properly cancel its positively frequency-dispersive counterpart from the CMBS so that constructive interference near the absorber can be obtained over a wide frequency band. Furthermore, the NFMS will compensate the surface conductance required for maximum incident power dissipation. As an example, we demonstrate an absorber with one-frequency decade bandwidth and a thickness of only 1/255 wavelength at the lowest operation frequency. The proposed concept enables versatile admittance matching techniques using a single-layered and has the potential to be used in the development of interesting low-profile and broadband microwave devices.

Photonics-Based Wideband Microwave Phase Shifter

A wideband microwave photonic phase shifter implemented based on a special dual-parallel Mach–Zehnder modulator (DP-MZM) consisting of two sub-MZMs and a polarization rotator is proposed and demonstrated. A microwave signal to be phase shifted is applied to the two sub-MZMs, via a 90° hybrid coupler, to generate two orthogonally polarized intensity-modulated optical signals, which are combined at a polarization beam combiner. A phase-shifted microwave signal is obtained by detecting the combined signal at a photodetector. The tuning of the phase shift is realized by tuning the DC bias voltages applied to the sub-MZMs. Since the phase shift tuning has been done electrically, high speed phase tuning can be implemented. The proposed phase shifter is experimentally demonstrated. A continuous phase tuning from 0° to 360° with small magnitude variations of less than ±1 dB and phase ripple standard deviation of less than 2.7° in a decade bandwidth from 2.5 to 25 GHz is realized. The system insertion loss is measured to be 10.8 dB. Investigation on the cause of magnitude and phase deviations is also performed by simulations, which are confirmed by experimental measurements.

Octave and Decade Printed UWB Rectifiers Based on Nonuniform Transmission Lines for Energy Harvesting

Ambient RF energy harvesting is a potential energy source for low-power and battery-less wireless sensors, enabling a range of applications from monitoring to security as part of the Internet-of-Things (IoT) scenario. One of the main challenges of ambient RF energy harvesting is the requirement of operation over a multitude of frequency bands of low ambient power densities resulting in a very wide aggregate operating bandwidth. In this paper, design examples of novel ultra-wideband energy harvesters are demonstrated with octave and decade bandwidths in the UHF and low microwave spectrum. The RF-dc conversion efficiency is maximized by tailoring the dimensions of a nonuniform transmission line used to provide broadband impedance matching. The design challenges in terms of impedance matching based on the Bode-Fano theoretical limit, losses and miniaturization are highlighted. Two prototypes are presented and their performance is evaluated. The octave band rectifier showed a measured RF-dc conversion efficiency of more than 60% over a frequency band of 470 to 860 MHz at 10-dBm input power. The decade band rectifier fabricated on Kapton substrate using inkjet printing featured a higher than 33% efficiency over a frequency band from 250 MHz to 3 GHz at 10-dBm input power.

Electrothermal Design of Bidirectional Wide-Boom Log-Periodic Antennas

A wide-boom, microstrip-fed planar bidirectional log-periodic (LP) antenna is proposed and improvements in its impedance match, radiation, and thermal performances are demonstrated. The boom width of each arm is increased by moving its virtual apexes into the other arm while preserving the small flare angle and self-complementarity. This modification widens the ground plane for the microstrip feed line and results in enhanced impedance match and gain. In addition, electrothermal multi physics analysis demonstrates that the wide-boom mitigates hot spots logarithmically developed on LP’s active regions. The impedance and far-field measurements show that the fabricated antenna achieves VSWR ≤ 2 and flat gain around 5 dBi over a decade bandwidth. A non contact thermal imaging system is used to measure temperature response of the antenna under a ~5 W input power over 1.71–1.85 GHz range. The measured temperature images correlate well with the multi physics simulations, therefore validating the conclusions obtained via electrothermal analysis.

Multi-Octave bandwidth, 100 W GaN power amplifier using planar transmission line transformer

In this paper, design, implementation, and experimental results of efficient, high-power, and multi-octave gallium nitride-high electron mobility transistor power amplifier are presented. To overcome the low optima source/load impedances of a large transistor, various topologies of a broadside-coupled impedance transformer are simulated, implemented, and measured. The used transformer has a flat measured insertion loss of 0.5 dB and a return loss higher than 10 dB over a decade bandwidth (0.4–4 GHz). The transformer is integrated at the drain and gate sides of the transistor using pre-matching networks to transform the complex optima source/load impedances to the appropriate impedances of the transformer plane. The measurement results illustrate a saturated output power ranged between 80 and 115 W with an average drain efficiency of 57% and gain of 10.5 dB across 0.6–2.6 GHz.

Designing and Packaging Wide-Band PAs: Wideband PA and Packaging, History, and Recent Advances: Part 1

In current applications such as communication, aerospace and defense, electronic warfare (EW), electromagnetic compatibility (EMC), and sensing, among others, there is an ever-growing demand for more linear power with increasingly greater bandwidth and efficiency. Critical for these applications are the design and packaging of wide-band, high-power amplifiers that are both compact in size and low in cost [1]. Most such applications, including EW, radar, and EMC testers, require high 1-dB compression point (P1dB) power with good linearity across a wide band (multi-octave to decade bandwidth) [2]. In addition to linear power, wide bandwidth is essential for high-data-rate communication and high resolution in radar and active imagers [3]. In modern electronics equipment such as automated vehicles, rapidly increasing complexity imposes strict EMC regulations for human safety and security [4]. This often requires challenging specifications for the power amplifier (PA), such as very high P1dB power [to kilowatt, continuous wave (CW)] across approximately a decade bandwidth with high linearity, reliability, and long life, even for 100% load mismatch [5].

Tailoring of the Brillouin gain for on-chip widely tunable and reconfigurable broadband microwave photonic filters.

An unprecedented Brillouin gain of 44 dB in a photonic chip enables the realization of broadly tunable and reconfigurable integrated microwave photonic filters. More than a decade bandwidth reconfigurability from 30 up to 440 MHz, with a passband ripple <1.9 dB is achieved by tailoring the Brillouin pump. The filter central frequency is continuously tuned up to 30 GHz with no degradation of the passband response, which is a major improvement over electronic filters. Furthermore, we demonstrate pump tailoring to realize multiple bandpass filters with different bandwidths and central frequencies, paving the way for multiple on-chip microwave filters and channelizers.

A Reactively Matched 1.0–11.5 GHz Hybrid Packaged GaN High Power Amplifier

An ultra-wideband PA using a single GaN die with resistive and reactive matching is fabricated and measured. The design includes series and shunt elements at the gate for stability and gain compensation, and uses two different substrates to obtain optimum ${\rm Z} _{0}$ ranges for the matching networks. CW measurements at 31 dBm source power show 27–48% PAE and 35.1–37.4 dBm output power from 1.0 to 11.5 GHz (168% relative bandwidth). These results demonstrate multi-watt output power and high PAE over a decade bandwidth, achieving the best results in this frequency range for a hybrid implementation.

0.8–8 GHz 4-bit MMIC phase shifter for T/R modules

This paper presents the design approach and test results of a full passive, decade bandwidth GaAs MMIC, composed by a phase shifter (PS) with a cascaded absorptive single pole double throwswitch, suitable for transmitter/receiver modules in active electronically scanned array. The proposed PS – fabricated using a UMS GaAs 0.25 PHEMT process – combines all-pass filters with high-pass filters, in order to provide less than 13 dB insertion loss, less than ±20° phase error and less than ±2.5 dB amplitude error in the 0.8–8 GHz bandwidth.

Comments on ‘Design and analysis of a decade bandwidth 180° hybrid coupler’

Comments on ‘Design and analysis of a decade bandwidth 180° hybrid coupler’

Integration of ultra‐wideband planar baluns into the Eleven feed

Integration of decade bandwidth baluns into the Eleven feed faces many challenges. The authors present a compact, low-loss and low-cost integration solution to the ultra-wideband balun feeding network for the dual-polarised Eleven feed in this study. The design procedures are described in detail. Evaluation of the balun integration based on the BOR1 (Body of Revolution type1) efficiency is introduced. Numerical simulations and measurements are presented for verifying the design. © The Institution of Engineering and Technology 2013.

A High Linearity VHF Programmable Gain LNA

A VHF (30MHz-300MHz) band digitally programmable low noise amplifier(LNA) has been implementedwith a 0.25um standard CMOS process for VHF CMMB mobile TV tuners. Utilizing a T-match input network, input matching of more than a decade bandwidth is achieved across all gain settings . Adoptingthe multiple gated technique, gain flatness enhancement and capacitor reuse etc. , the proposed LNA demonstrates 3 gain settings of 2 0 dB, 6 dB, - 9 dB with S11 below -12dB at every gain setting. At a power supply voltage of 2.5V, the LNA consumes less than 10mA curren t , -6dBm IIP 3 and a Noise Figure (NF) of less than 2.9 dB at 20dB gain setting over the VHF band.

HIGH PERFORMANCE MULTI-SECTION CORRUGATED SLOT-COUPLED DIRECTIONAL COUPLERS

In this paper a robust technique for the design of high performance directional couplers is proposed. It combines the advantages of wiggly coupled lines and slot-coupled lines but overcomes their main limitations. The key to this novel technique is a new corrugated slot that allows perfect compensation of the even and odd mode phase velocities and can be easily designed using Bloch- Floquet theory, yielding outstanding performance. To demonstrate the validity of the proposed technique, the design of two difierent wideband directional couplers is presented. The flrst design consists of a 10dB asymmetric directional coupler with a one decade bandwidth (1.2{ 12GHz) that exhibits a coupling accuracy of 10 § 0:6dB, a return loss better than 23dB and an isolation better than 28dB across the complete frequency band. The second design consists of a symmetric quadrature hybrid that operates over the complete UWB band (3.1 to 10.6GHz) showing an amplitude and phase imbalance between the output ports lower than §0:5dB and §0:7 - , respectively.

Design and analysis of a decade bandwidth 180° hybrid coupler

The design and analysis of a decade bandwidth 3 dB 180° hybrid coupler using tandem connection of two similar wideband 8.34 dB hybrids is presented. The designed coupler has return loss better than 12 dB over a decade bandwidth, insertion loss below 6 dB, amplitude balance within ± 1 dB, phase balance of ± 20° and isolation above 18 dB. Gap and overlap ground patterns at the junction of the tightly coupled to uncoupled region are introduced to improve isolation by preventing odd-mode field coupling and preserving equal even- and odd-mode phase velocities across the junction.