Broadband Matching Circuits Research Articles

Study of the characteristics of broadband matching antennas for fifth-generation mobile communications based on new composite materials

The presented research aims to analyze in detail the characteristics of broadband matching antennas specifically designed for 5G mobile communications applications, with an emphasis on innovative composite materials. The study focuses on a compact planar loop antenna designed for use on smartphones, covering the LTE/WWAN frequency bands 824 to 960 MHz, 1,710 to 2,690 MHz, and 3,300 to 3,600 MHz for full coverage of modern 5G networks. Experimental and numerical methods are used to broadly analyze the frequency range associated with 5G networks. The features of the use of composite materials in the implementation of antenna devices in 5G technologies are noted. A broadband matching circuit (BMC) with elements with lumped parameters and a reduced sensitivity invariant has been synthesized. A 3D model of the adaptive selective surface controller (SSC) was developed using CST Studio. The study results highlight the benefits of new composite materials in improving the performance of 5G antennas. This research makes a significant contribution to the development of 5G technologies by optimizing antenna design for efficient data transmission in modern mobile networks and can be a valuable resource for engineers and designers working in this field.

A 23–31 GHz high‐gain GaN low‐noise amplifier using T‐type matching networks and multiple feedback techniques for broadband 5G millimeter‐wave applications

AbstractA 23–31 GHz three‐stage low‐noise amplifier (LNA) based on 100 nm gallium nitride‐on‐Si technology is presented with a total circuit size of 2.0 × 1.4 mm2. To achieve an excellent noise figure (NF) and gain, a special inductive dual‐source feedback network is used; it contributes to noise matching and input conjugate matching by resonating with the parasitic gate‐source capacitance of the transistor. T‐type networks with low‐quality factor are carefully employed for broadband matching circuits to extend the bandwidth. Meanwhile, a lossy RLC feedback network of the output stage can further obtain a wider frequency band and improve the stability through Miller approximation analysis of the input quality factor and gain of the closed‐loop system. The proposed LNA achieves a NF of 1.9–2.5 dB, a small signal gain of 24–27 dB, and an output 1 dB compression point (P1dB) of 16 dBm across the band.

Electrically Small Wideband Monopole Antenna Partially Loaded with Low Loss Magneto-Dielectric Material

A miniaturized new topology of the planar monopole antenna using a Magneto-Dielectric Material (MDM) is proposed in this paper. The antenna element is realized by introducing slots partially covered by the MDM. We optimized and modified the MDM topology and dimensions to enhance the impact of this material on the planar monopole antenna, including slots in its structure. This new monopole shows a miniaturization rate of 60% of the antenna’s height (51 cm antenna’s height is miniaturized to 20 cm) by covering only 5% of the antenna surface by the MDM. The measured results show the antenna’s central working frequency of 130 MHz, while the bandwidth is 30% using a broadband matching circuit using the Real Frequency Technique (RFT).

Согласование антенного устройства канала управления и приемо-передающего модуля беспилотного летательного аппарата в условиях обледенения

The results of experimental studies of the antenna impedance of the control channel, an unmanned aerial vehicle in icing conditions are presented. A mathematical model of the antenna of the control channel of an unmanned aerial vehicle in icing conditions and without them is presented. The method of synthesis of broadband matching devices adapting radio engineering systems to varying load impedance in a wide range of natural conditions of their operation is shown. A broadband matching circuit has been synthesized for the antenna device of the control channel of an unmanned aerial vehicle in icing conditions, which provides a gain in the potentially achievable radio line range of up to 25% relative to the antenna device without a matching circuit.

A matrix-based design of broadband low-profile isolation and matching circuit for compact Wi-Fi/WLAN MIMO antenna arrays

A novel microstrip network is proposed for simultaneously controlling and improving the isolation and impedance matching in a highly-coupled printed monopole antenna array. This easy-to-fabricate network with a reduced number of key parameters including only an inductive microstrip line between two feeds, some functional simple links and two shorted stubs is designed in a small area. A matrix-based study on the total system along with an equivalent analysis method on the subsystem is presented to simplify the total study, noticeably. Network-based closed-form equations for real and imaginary parts of the self and mutual admittance of the antennas are extracted to establish the conditions and determine the parameters. A good agreement between the simulation and measurement of the prototypes is also provided. The results propose a broad bandwidth about 200 MHz at 2.45 GHz with an improved matching over 15 dB from 2.39 to 2.5 GHz. In this band, the isolation is improved over 32 dB with a maximum of about 70 dB. Using this network, not only good space diversity and high polarization purity are achieved, but also the correlation coefficient is reduced, notably. According to these suitable specifications, this efficient circuit can be a promising design for new compact MIMO-based Wi-Fi/Bluetooth/WLAN systems.

Метод синтеза широкополосных устройств с оптимальной характеристикой коэффициента преобразования мощности, согласующих изменяющийся во времени импеданс нагрузки.

A method is proposed for the synthesis of broadband matching devices that adapt radio engineering systems to the changing load impedance in a wide range of natural conditions of their operation. The results of experimental studies of the effect of operating conditions on the impedance of VHF and UHF radio antennas with matching devices are presented. An invariant of the sensitivity of the reflection coefficient function to changes in the load impedance is obtained, on the basis of which a complex criterion for the synthesis of broadband matching devices is developed. A broadband matching circuit was synthesized for the AD-44/CW-TA-30-512 antenna device, which provides a gain in the potentially achievable radio line range of up to 5% in relation to the standard matching device. An analytical mathematical model of a broadband matching device is developed and based on it, a matching device adaptive to the changing impedance of the AD-25/CW-3512 antenna is synthesized, providing an average gain in the potentially achievable range of the radio line from 2% to 15% in the framework of the presented experimental studies.

전자전용 S&C 대역 GaN 반도체 고출력증폭기 설계 및 제작

This paper describes the design and measurement results of an S to C-band gallium-nitride (GaN) solid-state power amplifier (SSPA) for an electronic warfare jammer. The S to C-Band GaN SSPA is fabricated, without wideband isolator, with multiple combined of 80 W GaN module using wide-band impedance matching topology and Super CMC (S-CMC) carrier structure, and designed small-sized broadband matching circuit using a cascaded 90° hybrid coupler for improve impedance mismatching performance between GaN DRA and GaN HPA. The S to C-band GaN SSPA for the electronic warfare, with a continuous wave (CW) RF injection condition over a frequency range of 2 to 6.5 GHz, demonstrated performance with a saturated average output power of 225 W (330 W peak output power), 21.39 % power added efficiency (PAE). Furthermore, with 1 % duty & 10 µs PW Pulse RF injection condition over an operation frequency range, it had performance with a saturated average output power of 287 W (404 W peak output power).

Methods for synthesis of matching circuits for broadband radio devices with unstable load impedance

The aim of this work is to select a synthesis method for a broadband matching circuit that provides maximum power transfer from a signal source to a load in the presence of a changing load impedance of a radio engineering device. To achieve this goal, an analysis of the main directions of designing broadband matching circuits (analytical, numerical, graphic-analytical synthesis methods) was carried out. Based on the results of a comparison of synthesis methods, their features (advantages and disadvantages) were indicated. The analysis of methods of synthesis of broadband matching circuits was carried out. For the analysis, the generalized Darlington method, the method of real frequencies, the structural-parametric synthesis method based on the T-matrix apparatus, and the graphic-analytical method based on the Volpert-Smith diagram were chosen). Using these synthesis methods, broadband matching circuits were obtained for various types of loads. Comparison of the results obtained was carried out according to several indicators: the level of the power transfer coefficient in the operating frequency range, the sensitivity of the power transfer coefficient to the change in the ratings of the elements of the matching circuit and the load impedance, provided that the number of elements of the matching circuit is no more than six. Based on the comparison and analysis, it was found that the most preferable synthesis method for solving the problem posed is the method of real frequencies. Its advantage is the use of a combination approach (iterative determination of the parameters of the resistance function with an analytical representation of the transfer function). Matching circuits obtained using this synthesis method provided the highest level of power transmission coefficient, as well as the lowest sensitivity value in a given frequency band for the considered types of loads.

The broadband reflectionless filtering and matching circuit operating with high transformation ratio

For matching transformed impedances, various methods are known in the literature that are used reactive, dissipative, and combined circuits. The operation of such circuits is possible either in a wide frequency band, but in the same standard paths, or in a narrow frequency band when matching impedances that differ from each other by a high transformation ratio. Unfortunately, with the help of known methods, it is impossible to matching impedances with a high transformation ratio and simultaneously to operating of the circuit in a wide frequency band. For a reflectionless high-pass filter, the task is to investigate the possibilities of expanding its operating frequencies band when matching impedances have high transformation ratio. For a typical reflectionless high-pass filter, the reflection coefficients of its two equivalent circuits operating in even and odd excitation modes are determined. They are used to find the frequency transmission coefficients for this device, as well as the transfer functions of the complex frequency. It is established that such device has a narrow band of operating frequencies when matching impedances have a high transformation ratio. Possible ways to expand the frequency band by introducing additional electromagnetic coupling to this device are considered. An absorbing filter-transformer with an additional electromagnetic coupling is investigated. The relations for calculating its main elements of the scheme are obtained. It is established that electromagnetic coupling in this device extends the operating frequencies band. Thus, when the magnetic coupling coefficient k tends to 1, this band can be expanded 1 1k2  times. The obtained theo- retical conclusions are fully confirmed by experimental results. The performed studies of reflectionless high-pass filter-transformer confirm the possibility of expanding the operating frequency band when matching impedances have high transformation. The proposed filter-transformer is recommended for use in the design of input matching circuits in power amplifiers using modern GaN transistors, for which broadband reflectionless matching is a necessary condition for eliminating parasitic excitations at low frequencies.

THE METOD OF SYNTHESIS OF QUASI-DUAL-BAND MATCHING DEVICE

The article presents some findings on the potential of analytical methods for the synthesis of broadband matching circuits for solving nontrivial circuit engeneering problems. Nontriviality shows itself in the technique for the assignment of the frequency response model (approximation) for the broadband synthesis in cellular communication, when double-band antennas are essential. The frequency response model appears as the result of frequency transformation, which yields in the assignment of both bands at the very first stage of the synthesis. The bands’width and isolation between them may be controlled independently, which is the essential part of the frequency transformation. Such way offrequency response assignment allows the potential of the method, which is always restricted by a load, to find broader application. In these conditions the frequency response turns to a quasi-double and asymmetrical one due to finite isolation between bands. We also present the general approach to the synthesis, which incorporates both the frequency transformation and novel synthesis technique. The modified frequency transformation can be applied to all types oftraditional approximations of arbitrary orders in synthesizing broadband frequency-selective matching devices. The distinctive feature of this technique is in the use of generalized Darlington’s synthesis for solving the problems of broadband matching of resistances in a lumped element basis with the application of frequency reponses obtained through modified frequency transformation. We have also estimated the efficiency of the developed technique by comparison with the known results.

A broadband 23.1 ∼ 27.2 GHz doherty power amplifier with peak output power of 24.3 dBm

Purpose This paper aims to implement a new high output power fully integrated 23.1 to 27.2 GHz gallium arsenide heterojunction bipolar transistor power amplifier (PA) to meet the stringent linearity requirements of LTE systems. Design/methodology/approach The direct input power dividing technique is used on the chip. Broadband input and output matching techniques are used for broadband Doherty operation. Findings The PA achieves a small-signal gain of 22.8 dB at 25.1 GHz and a saturated output power of 24.3 dBm at 25.1 GHz with a maximum power added efficiency of 31.7%. The PA occupies 1.56 mm2 (including pads) and consumes a maximum current of 79.91 mA from a 9 V supply. Originality/value In this paper, the author proposed a novel direct input dividing technique with broadband matching circuits using a low Q output matching technique, and demonstrated a fully-integrated Doherty PA across frequencies of 23.1∼27.2 GHz for long term evolution-license auxiliary access (LTE-LAA) handset applications.

Parallel-plate waveguide for volume radio frequency transmission in MRI.

Radiofrequency coils in MRI are narrowband resonant structures. The high-quality factor makes their performance sensitive to loading and other operating conditions. We developed a new coil to provide volume transmit in a broad frequency band. The proposed coil is a parallel-plate waveguide. When operating in the transverse electromagnetic mode, a uniform magnetic field is generated between the plates for imaging. The impedance of the transverse electromagnetic mode is matched by a broadband matching circuit. The two plates are actively driven with broadband Wilkinson power dividers and combiners. Re-entrant design is further applied to improve the overall efficiency. We developed a prototype of a coil to image the human forearm with a bandwidth of more than one octave. Its feasibility was demonstrated by proton imaging and phosphorous spectroscopy at 7T. The proposed coil structure is compact and relatively easier to construct. It can be applied for volume radiofrequency transmit in MRI in a broad frequency band.

Electrically Small Broadband VHF/UHF Planar Antenna Matched Using a Non‐Foster Circuit

ABSTRACTA broadband non‐Foster matched Planar Inverted‐F Antenna is proposed for 100–500 MHz VHF/UHF handheld terminal applications. The proposed design shows that in the lower frequencies antenna gain improvement of as much as 25 dB can be obtained with the help of the broadband matching circuit for a small antenna on a 0.05 wavelength ground plane at the lowest frequency. The issues of RF power versus matching and circuit stability are pointed out. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2494–2497, 2013

Approximate synthesis formulas for microstrip line with aperture in ground plane

Approximate closed-form expressions for the propagation characteristics of a microstrip line with a symmetrical aperture in its ground plane are reported in this article. Well-known expressions for the characteristic impedance of a regular microstrip line have been modified to incorporate the effect of this aperture. The accuracy of these expressions for various values of substrate thickness, permittivity and line width has been studied in detail by fullwave simulations. This has been further verified by measurements. These expressions are easier to compute and find immense use in the design of broadband filters, tight couplers, power dividers, transformers, delay lines, and matching circuits. A broadband filter with aperture in ground plane is demonstrated in this article. (c) 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012.

Design of Broadband Impedance Matching Circuit for PLC Coupler using Butterworth Equalizer

This paper represents design broadband impedance matching circuit for Coupler to improve power transfer efficiency in the broadband power line communication(BPLC) systems. The Butterworth gain function equalizer is used to design broadband matching circuit. A practical PLC Coupler impedance matching circuit is designed, and the characteristics for S11 and S21 of PLC Coupler are enhanced comparing with unmatched one. This is done by maximizing the power transfer gain from modem to the load.

Design of HTS coplanar waveguide matching circuit for low noise CMOS-HTS receiver

For realizing a single chip HTS integrated microwave receiver, a superconducting slot antenna and a Si-CMOS low noise amplifier (LNA) combined with a broad band matching circuit composed of coplanar waveguide (CPW) meanderline resonators has been designed and tested. By applying the filter technique and using admittance inverters (J inverters), we propose a new design method of CPW broadband impedance matching circuit connected to low and high impedance loads such as HTS antenna and CMOS device. Based on the design method, we designed a Chebyshev type impedance matching circuit connecting with slot antenna and CMOS-LNA at 10 GHz center frequency. More over, in order to increase the antenna directivity, we designed 2-dimensional antenna array by folding the slot antenna.

Improving amplifier stability through resistive loading below the operating frequency

A new design method for a stable RF amplifier using a broadband-matched 3-dB coupled line is proposed in this paper. The proposed broad-band matching circuit consists of lossless matching circuits at operating frequency band and resistive matching circuits at frequencies below the operating band. This design method improves the stability of the amplifier and is suitable for the design of a power amplifier and multistage amplifier. When applying this proposed method to a design of a two-stage power amplifier for personal communication systems, measured results show 18.0dB gain and 9 W (39.5 dBm) output power.

Broadband electronically tunablemicrostrip ring resonator filterwith negative resistance coupling

Broadband electronically tunable filters can be realised using varactor tuned ring resonators with negative resistance coupling. Broadband matching circuits must be used for negative resistance realisation and for compensating the input and output impedance variation with frequency. Circuits and simulated results for a two section 1.3 to 2.1 GHz silicon varactor tuned 50 to 70 MHz bandwidth ring resonator filter are presented.

DESIGN AND IMPLEMENTATION OF MICROWAVE PARTS OF AIRBORNE-RADAR-WARNING RECEIVERS

The radar warning receiver (RWR) is the heart of the self protection system of modern aircraft. The most important receiver structures that can be used as RWR are the crystal video receiver (CVR) and the instantaneous frequency measurement (IFM) receiver. This paper presents a complete design and implementation of the microwave part of the CVR. This CVR is designed to cover a frequency ranging from 1.5 up to 4 GHz. The CVR is implemented using the recently developed microstrip technology. The designed receiver was successfully tested and the results in terms of the output voltage and the voltage standing wave ratio (VSWR) were very good. This paper presents also a complete design and implementation of the critical components of the IFM receiver. These components are the phase correlator, the power dividers, the delay line, the square law detectors preceded by broadband matching circuits, and the low pass filter. They are implemented using the microstrip technology. The input to the correlator is the threatening radar signal and the output comprises four video signals that can be processed to obtain the signal frequency instantaneously. A new design procedure is proposed to overcome the problems, usually encountered when trying to design and implement phase correlators. The designed correlator was successfully tested and found to operate adequately in the whole S-band.

Theoretical analysis and fundamental characteristics of triplate spiral inductors

AbstractThis paper presents a theoretical analysis and examples of triplate spiral inductors. The analysis is based on low‐frequency band transmission line theory, from which three different transmission line circuits are used to model the inductor. After obtaining the circuit impedances for different potential distributions, we deal with the high‐frequency problem using a model where the interline field couplings are simulated as lumped capacitances. Based on these techniques it is possible to investigate basic properties such as the inductances, self‐resonant frequencies and losses.Triplate inductors may be used as three‐dimensional (3‐D) hybrid IC elements in the UHF band (0.3–3 GHz), for example, in broadband matching circuits, various filters, and decoupling circuits for power supply lines.