Impedance Matching Network Research Articles

RF energy harvesting using Sierpinski’s gasket fractal antenna with EBG geometry

In this paper presented antenna design of Sierpinsiki’s gaskets fractal antenna with and without EBG geometry has been demonstrated. Proposed antenna has been introduced at a frequency of 6.74 GHz for Radio frequency (RF) harvesting systems. RF energy can be converted into DC power with the help of antenna, impedance matching network and rectifier. The proposed antennas were simulated using IE3D software. Simulated results of both antennas have been introduced and the same antennas were fabricated with FR4 substrate and tested using vector network analyzer. Simulated Results of return loss, efficiency was shown. Simulated and measured results were compared. There is some deviation in the measured results, because of inaccuracy in physical dimension while fabricating manually.

A New Design Methodology for Wideband Analog Predistorter With the Characteristics of Frequency-Dependent Gain and Phase Conversions

A novel design method, which can transform the nonlinear circuits design to the impedance matching network (IMN) design, is proposed for wideband analog predistoter (APD) with the characteristics of frequency-dependent gain and phase conversions in this paper. First, the design method for the desired gain and phase conversions is introduced. The ABCD parameters of the IMN can be computed. To simplify the design, the obtained parameters are transformed to the IMN terminal impedance. Then we can only need to design the IMN terminal impedance to obtain the desired transfer characteristics. In the meanwhile, an APD with 4.5 dB gain conversion and 50° phase conversion is designed and simulated to validate the design method for specify gain and phase conversions. The simulated results show good effectiveness of the design method. Second, for wideband application, the complex gain and phase conversions surface design is transformed to the IMN terminal impendence curve versus frequency design. This gives the designers a well-defined strategy for wideband APD design focusing on frequency-dependent phase conversion as well as gain conversion. To validate the proposed method, a wideband APD operating at K-band (17-20 GHz) is designed, fabricated and measured. A linearized 100W K-band TWTA is shown to achieve a noise power ratio (NPR) >20 dB at 3 dB output power back-off, and phase change <; 6.5° among the operating band.

Monopole Antenna on Transparent Substrate and Rectifier for Energy Harvesting Applications in 5G

In line with the harvested energy required for the emerging 5G technology, this article proposes a planar monopole antenna and a rectifier. The proposed Coplanar Waveguide (CPW)-fed antenna is printable on a transparent Poly-Ethylene Terephthalate (PET) substrate. The antenna has a center frequency at 3.51 GHz within a bandwidth of 307 MHz that covers the pioneer 5G band in Malaysia. The designed omnidirectional antenna exhibits the maximum gain of 1.51 dBi with a total efficiency of 95.17 percent. At the antenna frequency, a rectifier has been designed with the voltage doubler technique on a Rogers RO3003 substrate. Over an input RF power of 0 dBm, the rectifier has a power conversion efficiency around 42 percent. The proposed antenna rejects harmonics at least until 16 GHz frequency that makes it compatible with the rectifier to eliminate an additional bandpass filter or impedance matching network from the energy harvesting system.

High-Power Wire Bonded GaN Rectifier for Wireless Power Transmission

A novel wire bonded GaN rectifier for high-power wireless power transfer (WPT) applications is proposed. The low breakdown voltage in silicon Schottky diodes limits the high-power operations of microwave rectifier. The proposed microwave rectifier consists of a high breakdown voltage GaN rectifying element for high-power operation and a novel low loss impedance matching technique for high efficiency performance. Wire bonding method is adopted to provide electrical connection between GaN chip and board which induces undesirable inductance. In order to realize high efficiency performance, an impedance matching network is proposed to exploit the unavoidable inductance along with a single shunt capacitor, resulting in a low loss matching circuit to achieve a compact high-power rectifier. The fabricated GaN rectifier exhibits a good performance in the high-power region and can withstand up to 39 dBm input power before reaching the breakdown limit at the operating frequency of 0.915 GHz and load resistance of 100 Ω. It has a compact size and exhibits high efficiency performance in high-power region (achieved a maximum efficiency of 61.2% at 39 dBm), making it suitable for high-power applications like future unmanned intelligent devices and WPT in space applications.

Decoupling and Matching Strategies for Compact Antenna Arrays

This paper proposes and evaluates three strategies of joint decoupling and impedance matching networks (DMN) for antenna arrays. Since MIMO technology presents antenna arrays which can be formatted with elements of the order of tens to hundreds, several effects due to this structure have emerged, such as mutual coupling and impedance matching among antenna elements in array. Therefore, the treatment of these issues seeks to solve problems such as the degradation of the performance of the communications system. The first method called DMN with Lumped Elements (DMN-LE) performs the decoupling and impedance matching steps with capacitors and inductors. The second method is called DMN with Ring Hybrid (DMN-RH). It utilizes a microstrip line in the ring form. With this approach is due achieves first the decoupling followed by impedance matching step. The third method is called Networkless Decoupling and Matching (NDM). It brings a concept of decoupling without the presence of a network itself. This enables modeling an antenna array that performs DMN operations in a simplified and compact manner. A comparison of the methods is performed bothanalytically and via computer simulations. We conclude that the third method is promising new alternative approach.

Design of WPT RF Power Supply Based on Dual Directional Coupler and Capacitor Array Impedance Matching Network

In the engineering use of a magnetically coupled resonant radio energy transmission system, both the resonant frequency and the optimal load impedance will be varied because of the external conditions. In view of the above problems, this paper proposes an RF power supply with adjustable frequency and optimal load impedance, in order to achieve efficient power transmission for different frequency radio energy transmission systems and different load conditions. The RF power supply is mainly composed of a frequency controllable signal generator, a Class E power amplifier circuit, a dynamic impedance matching network, a load detection circuit and a controller. Through the above parts, the load tracking of the RF power supply can be realized, and the higher output efficiency can be realized under the condition of changing the working frequency and the load. Finally, the feasibility of the proposed RF power supply is verified through experiments. The experimental results show that the RF power supply can automatically track changes in the operating frequency and load range, and the output efficiency can be maintained at more than 75%.

Gain enhanced conformal patch antenna with defected ground for aircraft applications

This study describes a design of conformal patch antenna for airborne applications especially in measuring the velocity of ocean and river current. By considering the decorrelation time, precipitation, resolution, and size of the antenna, the current system operates within the C-band frequency range of 5.05-5.45 GHz. This design has achieved a bandwidth of 7.7% that helps in increasing the cross-range resolution. A maximum gain of 10 dB is achieved at the bore side angle. The normalised side lobe level (SLL) of -26 dB reduces aliasing by achieving higher pulse repetition rate. Defected ground structure (DGS) is used for suppressing higher harmonics and its effect has been explained with simulation results. As most aircrafts are made of carbon fibre composites (CFC), this antenna has been checked by mounting on CFC sheets for real-time analysis and shows good performance in terms of both measured and simulated results. The transmission line model of the proposed patch antenna and impedance matching network is also described with the corresponding circuits. The characteristic mode analysis is carried out to study the intuitive behaviour and to optimise the performance of patch antenna by analysing the performance metrics of different current modes.

A Full-Band Digital Television Transmitting Antenna Array With Dual-Layer Bowtie Dipole Unit

A full-band digital television (DTV) transmitting antenna array with dual-layer bowtie dipole unit is proposed in this paper. The dual-layer bowtie dipole is utilized as the antenna unit to broaden the frequency bandwidth, and its key parameters are discussed. Besides, a wideband impedance matching network with stepped complex impedance transformers is designed to achieve the full-band low voltage standing wave ratio (VSWR). For verification, a prototype is designed, fabricated, and measured. The experimental results agree well with the simulations. The measurement shows a relative bandwidth of 62.4% (455 MHz - 868 MHz) under the criterion of VSWR <; 1.15. Particularly, the VSWR is less than 1.13 within the range of 470 MHz - 862 MHz, (i.e. the full band of the DTV transmitting system). And the proposed antenna maintains a stable gain larger than 11.6 dBi over the operating frequency band with the half-power beam width of $70^{\circ } \pm ~3^{\circ }$ in the horizontal plane, which meets the requirements of the full-band signal transmission in the DTV broadcasting system.

An Image Rejection Ku-Band CMOS Low Noise Amplifier With Bridged-Tee Band-Stop Filter

For satellite communication applications, this paper presents an image rejection Ku-band low noise amplifier (LNA) in a 65-nm CMOS process for the Hartley receiver architecture. To achieve high input/output linearity performance, the inductive source degenerated cascode and the capacitive neutralized common-source (CS) amplifier topologies are used in the LNA input and output stages, respectively. To achieve wideband input return loss, the minimum noise figure and high gain performance simultaneously, the inductive source degenerated cascode amplifier is co-designed with the fourth order input impedance matching network. For the image rejection purpose, a bridged-tee band-stop filter is proposed. The measurements show the LNA achieves 14.3-to-18.3 GHz 3 dB bandwidth with 17-to-20 dB power gain, 3.5-to-4 dB noise figure, 17-to-37 dB image rejection and -5 dBm IIP3. Including all pads, the chip occupies a silicon area of 1360 × 450 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and consumes 72 mW DC power.

Design of Compact Dual-Band RF Rectifiers for Wireless Power Transfer and Energy Harvesting

In this paper, we propose a compact dual-band impedance matching network (DBIMN) for radio frequency (RF) rectifiers. The DBIMN is achieved with a single-stage T-type network, with only three segments of the transmission line. We investigate the closed-form design equations, as a design guideline of the DBIMN. In addition, we propose the design methodology of the rectifier using the DBIMN. For validation, we design two dual-band rectifiers (0.915 and 2.45 GHz), for different input power levels. The rectifier with high input power level, is designed for a wireless power transmission (WPT) system. With a 12 dBm input power, the measured power conversion efficiencies (PCEs) are 81.7 and 73.1% at the working frequencies. The PCEs becomes 69.2 and 64.1% (at −1 dBm input power) for the low-power input rectifier that can be used in an RF energy harvesting (RF-EH) system. The simulated and measured results match each other well. Compared with previous designs, the proposed designs have advantages in compactness and high efficiency.

Harmonic distortion considerations for an integrated WPT-PLC system

AbstractThis paper presents design considerations for an integrated wireless power transfer (WPT) and power line communication (PLC) system (e.g. WPT-PLC). The main goal is to enable wireless charging of mobile electronic products, along with high data rate communication over the shared wireless inductive resonant channel. Starting from a couple of resonant coils, characterized by the S-parameters matrix, the design of an impedance matching network and decoupling filters is carried out to better decouple power and data signals. A pulse-driven class-E power amplifier (PA) and a rectifier are first conceived based on the measured S-parameters and load-pull characterizations. Second, a sine-driven class-E power link, operating at 6.78 MHz, is proposed to reduce the total harmonic distortion of the integrated WPT-PLC system. These design steps aim to ensure high-power efficiency and low harmonic distortion of the class-E PA in order to mildly affect the channel capacity of the PLC. The harmonic interferences of the pulse-driven and sine-driven class-E power links are compared and discussed, together with the electromagnetic compatibility levels, the channel capacity, and the noise disturbances of the PLC channel in order to guarantee an optimized power and data transfer in the integrated WPT-PLC system.

Novel Switchable Filtering Circuit With Function Reconfigurability Between SPQT Filtering Switch and Four-Way Filtering Power Divider

In this article, we propose a circuit model for designing the switchable filtering circuit with reconfigurable functions between a single-pole quad-throw (SPQT) filtering switch (State 1) and a four-way filtering power divider (State 2) without additional switchable impedance matching network (IMN). The proposed circuit model can be utilized as the feeding network of a switchable directive and omni-directional antenna system to eliminate the omni-directional antenna in conventional solutions to reduce the size and cost. It consists of four filter channels with a common port. In State 1, it works as a SPQT filtering switch, where only one channel is turned on to realize good filtering responses and the impedances at the other three channels are adapted to infinity to realize high isolation. The four channels are turned on simultaneously in State 2 to work as a four-way filtering power divider, and the input impedance of the common port is the same as that in State 1. Thus, a switchable IMN is not required for port matching when switching between the two states. Transmission zeros are generated to enhance the skirt selectivity. For verification, the filtering circuit is constructed using high-$Q$ coaxial resonators. Experimental results show excellent performance in both states acting as a SPQT filtering switch and a four-way filtering power divider.

Design and Analysis of a Single-Band Printed Rectenna Circuit at WiFi Frequency for Microwave Power Transmission

In this paper, a single-band printed rectenna of size (45×36) mm2 has been designed and analyzed to work at WiFi frequency of 2.4 GHz for wireless power transmission. The antenna part of this rectenna has the shape of question mark patch along with an inverted L-shape resonator and printed on FR4 substrate. The rectifier part of this rectenna is also printed on FR4 substrate and consisted of impedance matching network, AC-to-DC conversion circuit and a DC filter. The design and simulation results of this rectenna have been done with the help of CST 2018 and ADS 2017 software packages. The maximum conversion efficiency obtained by this rectenna is found as 57.141% at an input power of 2 dBm and a load of 900 Ω.

Modelling, design and fabrication of a novel reconfigurable ultra‐wide‐band impedance matching based on RF MEMS technology

This study proposes an adaptive impedance-matching network with tremendously reduced dimensions and presents its fabrication process. The proposed radio-frequency micro-electromechanical system (RF MEMS) device is based on a coplanar waveguide design and relies on suspended bridges for impedance tuning. The tuning is controlled by a variable applied DC voltage to the bridges. Preliminary tests validate the device's operation mechanism, and simulations were performed on both the mechanical aspects of the device (bridge gap manipulation) and tuning capabilities. This device presents the possibility of operating in a wide band of frequencies, namely [1–6] GHz, and for load impedances in the interval of [30–90] Ω for the real part and [−10–30] for the imaginary part. The device's resonant frequency and its bandwidth can be modified easily by changing the bridge gap in the RF MEMS.

A Switchless SiGe BiCMOS Bidirectional Amplifier for Wideband Radar Applications

This brief presents a switchless bidirectional amplifier (BDA) with 7-to-30 GHz of bandwidth (BW) and 11.2 dB of peak gain. Common impedance matching networks (IMN) are utilized for both directions, to form a low power and compact amplification stage. It achieves +0.58 dB/BW of a gain slope, which reaches its peak value at 21 GHz. Its output-referred 1-dB compression point (OP1dB) and group delay (GD) are measured as −2.5 dBm and 41 psec. while having ± 1.5 dB and ± 9.1 psec. variation over the defined BW. Moreover, the BDA dissipates 14 mW of power in 0.42 mm2 of area (including pads). The measurement results demonstrate that the BDA is compatible with the wideband transceiver systems. To the best of the authors’ knowledge, the presented design has the best operating bandwidth with a positively sloped gain without sacrificing from the area, power consumption and other remaining RF features such as noise figure (NF).

Compact Analog Predistorter With Shape Tuning Capability Using Power-Dependent Impedance Matching Network

This brief presents a novel shape tunable reflective analog predistortion (RAPD) linearizer with a simple structure. The power-dependent impedance matching network (PIMN) based on parallel Schottky diode is applied to the RAPD linearizer to achieve the shape tuning function. Influence of the PIMN on the impedance of the nonlinear load is analyzed in detail. Two different types of shape tunable linearizers for the solid state power amplifier (SSPA) and the travelling wave tube amplifier (TWTA) are proposed and simulated. The shape tuning capability has been verified by a fabricated C-band RAPD linearizer. Good linearity improvement has been achieved for a C-band 20 W SSPA with the proposed linearizer.

Construction of a gigahertz-bandwidth radio-frequency scanning tunneling microscope based on a commercial low-temperature system

The highest frequency of the electric signal that a conventional scanning tunneling microscope (STM) can process typically lies in the kilohertz regime, imposing a limitation on its temporal resolution to the submillisecond regime. When extracting (feeding) the high frequency, or radio-frequency (RF), signal out of (into) the tunnel junction, the most challenging part is that the tunnel junction has a very high impedance, causing significant reflections. Here, we present a systematic solution on the construction of RF-STM with high sensitivity. To minimize radiation loss, using coaxial cables as conducting wires, we designed an active impedance matching network (IMN) based on a field-effect transistor, which can provide impedance matching over a wide frequency range and can bridge the enormous impedance difference associated with the tunnel junction. To shorten the signal cable before amplification, the STM probe itself was directly mounted on the IMN as the input pin, which is an unprecedented attempt to minimize the undesired parasitic capacitances. Furthermore, we employed a two-stage cryogenic SiGe low noise amplifier and a high-end spectrum analyzer to amplify and subsequently analyze the RF signal of interest. After this systematic engineering, the bandwidth of our STM has been improved to the gigahertz regime, implying a six orders of magnitude improvement. The sensitivity level of our newly built RF-STM is measured to be better than 1.0 pA/√Hz at 200 MHz at 78 K. The RF-STM also finds its application in nanoscale thermometry. Our efforts in its instrumentation should contribute to the development of high frequency scanning tunneling microscopy.

Modified Q-Based Real Frequency Design of Narrowband Impedance Equalizer with Complex Terminations

In this paper, real frequency design equations of narrowband impedance matching network with complex terminations are derived; which are used to design L, Pi and T type of networks. In the approach, there is no need to have termination models with component values, it is enough to have measurement values of termination impedances. A few examples are solved to exhibit the merits and application of the derived equations.

A Review of Impedance Matching Techniques in Power Line Communications

Impedance mismatch that degrades signal power transfer and affects communication reliability is a major obstacle for power line communications (PLC). Impedance matching techniques can be designed to effectively compensate for the impedance mismatch between PLC modems and power line networks at a specific frequency or for a given frequency band. In this paper, we discuss the tradeoffs that need to be made when designing an effective impedance matching network. We also make a comprehensive review of previous state-of-the-art PLC impedance matching techniques and provide a useful classification of each technique. Finally, we discuss important issues (concerns) and provide suggestions for research directions deserving more attention. This review provides a useful guideline for researchers and manufacturers to quickly understand impedance matching principles and facilitate the design of an effective impedance matching coupler for PLC applications.

Integrated cmos rectifier for rf-powered wireless sensor network nodes

This article presents a review of the CMOS rectifier for radio frequency energy harvesting application. The on-chip rectifier converts the ambient low-power radio frequency signal coming to antenna to useable DC voltage that recharges energy to wireless sensor network (WSN) nodes and radiofrequency identification (RFID) tags, therefore the rectifier is the most important part of the radio frequency energy harvesting system. The impedance matching network maximizes power transfer from antenna to rectifier. The design and comparison between the simulation results of one- and multi-stage differential drive cross connected rectifier (DDCCR) at the operating frequencies of 2.44GHz, and 28GHz show the output voltage of the multi-stage rectifier doubles at each added stage and power conversion efficiency (PCE) of rectifier at 2.44GHz was higher than 28GHz. The (DDCCR) rectifier is the most efficient rectifier topology to date and is used widely for passive WSN nodes and RFID tags.