Coplanar Technology Research Articles

Design and Development of Compact Wilkinson Power Divider on Gallium Nitride Coplanar Technology

In this article, an ultra-compact monolithic microwave integrated Wilkinson power divider (WPD) was accomplished for X-band applications. So as to reduce the size of the design, the miniaturization technique was illustrated with the theoretical analysis. After the theoretical analysis, the layout of the design and electromagnetic simulation were performed. The proposed Wilkinson power divider was manufactured with utilizing gallium nitride integrated passive device technology. In the measurement results, it was seen that the input and output (I/O) reflection coefficients were better than -15 dB in the frequency bandwidth of 8-12 GHz. In addition, the insertion loss was measured less than -4 dB in the X-band (8-12 GHz). Moreover, the 15-dB fractional bandwidth is 40% and the isolation between the outputs are better than -15 dB. The size of the proposed Wilkinson power was reduced to the dimensions of 700 m  700 m (0.047 λg x 0.047 λg, where λg is the wavelength value at the center frequency (10 GHz)), as 𝜋-type miniaturization technique was employed with monolithic lumped components. Beside its miniaturized size, the proposed power divider exhibits broadband characteristics while having any degradation in the electrical performance.

Dosimetric investigation of non-coplanar field technology in static intensity-modulated radiation therapy for gastric carcinoma

Objective To compare the dosimetric characteristics of non-coplanar and coplanar field technology in static intensity-modulated radiotherapy of gastric cancer patients, so as to provide a reference for clinical radiotherapy plan selection. Methods Thirty-six patients with gastric cancer were selected to receive intensity-modulated radiotherapy in Huanggang Central Hospital, which was designed plan A and B. Group A used 7-field coplanar technology, while Group B used 7-fleld non-coplanar technology. We compared the differences of the optimized monitor unit, the dosimetry of organs at risk and target areas between group A and group B. Results Both group A and B could meet the requirements of doctors. The homogeneity index (0.14 ± 0.02), the conformity index (0.98 ± 0.01), D min (4 315.21 ± 16.74) cGy, D mean (4 679.28 ± 28.39) cGy and D max (4 952.30 ± 33.26) cGy of target areas in group B were better than those of group A. Moreover, the monitor unit of group B was much lower than that of group A, and the difference was statistically significant ( P < 0.05). The D max, D mean, V 15, V 20 and V 30 of the left and right kidneys in group B were lower than those of group A. The D max (3 408.57 ± 46.03) cGy, D mean (1 250.32 ± 14.27) cGy and V 20 (44.91% ± 6.67%) of spinal cord and the D max (3 408.57 ± 46.03) cGy, D mean (1 720.55 ± 17.42) cGy, V 20 (25.31% ± 7.78%) and V 30 (18.52% ± 1.56%) of small intestine were also lower than those of group A. The differences were statistically significant ( P < 0.05). Conclusion The non-coplanar field radiation plan has more advantages in terms of target dose distribution and protection of organs so that it can be more considerably used in the process of planning and design. 摘要： 目的 通过比较非共面射野与共面射野计划在胃癌静态调强中的剂量学特点, 为临床放疗计划选择提供依 据。 方法 选取黄冈市中心医院接受调强放射治疗的胃癌患者 36 例, 每名患者均设计A、B 2 组计划, A 组采用 7 野 共面技术, B 组采用 7 野非共面技术, 比较 A 组和 B 组优化后机器跳数、危及器官和靶区的剂量学差异。 结果 A、B 两组计划均能满足医生要求, B 组靶区均匀性指数 HI (0.14 ± 0.02)和适形度指数 CI (0.98 ± 0.01), 靶区 D min (4 315.21 ± 16.74) cGy, D mean (4 679.28 ± 28.39) cGy 和 D max (4 952.30 ± 33.26) cGy 均优于 A 组, 且 B 组机器跳数更 少, 差异有统计学意义 ( P < 0.05)。B 组左右侧肾脏 D max、 D mean、 V 15、 V 20 和 V 30均低于A组, 脊髓的 D max (3 408.57 ± 46.03) cGy、 D mean (1 250.32 ± 14.27) cGy 和 V 20 (44.91% ± 6.67%)以及小肠的 D max (3 408.57 ± 46.03) cGy、 D mean (1 720.55 ± 17.42) cGy、 V 20 (25.31% ± 7.78%) 和 V 30 18.52% ± 1.56%)也均低于 A 组, 差异有统计学意义 ( P < 0.05)。 结论 非共面射野计划在靶区剂量分布和危及器官保护上更优, 计划设计过程中可以更多的考虑非共面布野技术。

Design of high-performance microstrip and coplanar low-pass filters based on electromagnetic bandgap (EBG) structures

In this paper, a rigorous method for the design of high-performance n-order Chebyshev low-pass filters based on electromagnetic bandgap (EBG) stepped impedances in microstrip and coplanar (CPW) technologies is proposed. Fifth-order low-pass filters implemented by means of circular patterns etched in the ground plane of microstrip and CPW lines have been designed, simulated and measured on an RO3010 substrate (∊r= 10.2, tanδ = 0.0023 at 10 GHz, substrate thickness h = 0.635 mm and copper thickness t = 0.018 mm). The designed filters have shown a good agreement between EM simulation and measurement results. The proposed EBG-based low pass filters, with six etched circles and a size of 42 × 20 mm2, achieve a passband with a cut-off frequency fc = 6 GHz measured at |S11| = −20 dB, return loss RL = 20 dB, 5 reflection zeros in the frequency axis, a ripple lower than 1.1 dB, and a stopband greater than 5 GHz with a rejection level higher than 30 dB. Therefore, the designed low-pass filters have an ultra-wide passband with high return loss, low insertion losses and a low ripple. In addition, they exhibit a large stopband with high rejection level compared to other reported wide stop-band low-pass filters based on EBG, defected ground structures (DGS), or modified complementary split ring resonators (CSRR). This technique can be used to design high-performance Chebyshev EBG-based low-pass filters with a high degree of control over the characteristics of their frequency responses. This allows to replace the EBG-, DGS- and CSRR-based wide stop-band low-pass filters in microwave circuit and antenna applications, with filter structures exhibiting high return loss, equiripple responses in the passband, and high rejection level in the stopband.

Designing gallium nitride-based monolithic microwave integrated circuits for the Ka, V, and W bands

A technology for fabricating multifunction monolithic microwave integrated circuits (MMICs) based on gallium nitride (GaN) heterostructures, which operate at the frequency range up to 100 GHz (the Ka, V, and W bands), is developed. Power amplifier (PA) MMICs operating at 90 GHz are fabricated using the coplanar technology with the gain coefficient being up to 15 dB and the specific output power exceeding 500 mW/mm. In addition, microstrip technology with the use of the polymer dielectric and grounding metallization over the wafer surface without through holes in the substrate is approved. The parameters of the MMICs for multifunction single-chip transmit-receive modules (TRMs), as well as the parameters of the MMICs for intermediate-frequency amplifiers (IFAs), voltage-controlled oscillators (VCOs), low noise amplifiers (LNAs), PAs, and balanced mixers operating in the Ka and V bands (up to 70 GHz), which are fabricated using the proposed technology, are presented.

New Formulation of the Mulilayer Iterative Method: Application to Coplanar Lines with Thick Conductor

The skin effect is an electromagnetic phenomenon that makes the current flows only on the surface of the conductors at high frequency. This article is based on the phenomenon to model a structure made in coplanar technology. In reality, these types of structures integrated metal layers of different thickness of copper (9 μm, 18 μm, 35 μm, 70 μm). The neglect of this parameter introduces errors, sometimes significant, in the numerical calculations. This is why an iterative method (FWCIP) based on the wave concept was restated. Validation of results was carried out by comparison with those calculated by Ansoft HFSS software and Agilent ADS Technology. They show a good matching.

Optimization of a microelectromechanical systems (MEMS) approach for miniaturized microcantilever-based RF microwave probes

In this study, microelectromechanical systems (MEMS) technology-based miniaturized microwave ground-signal-ground (GSG) probes are designed, fabricated, tested and optimized in the context of on-chip microwave characterization of the miniaturization of microelectronics. The probe structure is designed using coplanar technology on a micrometre scale. In contrast to conventional macroscopic on-wafer probing structures, a 2μm width signal line and 2.5μm width spacing between signal and ground conductors are demonstrated. The microcantilever-based probe structure is optimized to ensure good radio frequency (RF) performances. The fabrication steps of the probe structures have been developed by means of MEMS technologies using silicon-on-insulator (SOI) wafers. Hundreds of probe structures have been fabricated on a single 3inch diameter SOI wafer–the fabrication yield is close to 100%. Measurement performances demonstrated using a back-to-back probe structure exhibit return loss better than 15dB and insertion loss lower than 2.5dB (∼1.8dBmm−1) up to 50GHz. Measurements indicate that a microcantilever composed of a 20μm thick, high resistivity silicon device layer of SOI performs well up to 50GHz—agreeing well with previous microelectromechanical modelling. DC measurements exhibit a very low contact resistance (0.02Ω). Finally, on-wafer RF measurements using the miniaturized probes have been achieved using direct probing onto a CPW load (68Ω) up to 4GHz by coupling a vector network analyser (VNA) to a scanning electron microscope (SEM).

Determination of the complex permittivity of microfluids in a microstrip geometry

ABSTRACTA novel configuration for estimating the broadband permittivity of small fluid volumes is presented using 2‐port S‐parameters. Unlike previous demonstrations in coplanar technology, our proposal places the analyte under a microstrip trace where better field overlap with the fluid improves device sensitivity. Fluid parameter estimates based on simulation are presented. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2604–2608, 2014

AN NUMERICAL METHOD BASED ITERATIVE PROCESS TO CHARACTERIZE MICROWAVE PLANAR CIRCUITS

In the present work, the modeling of microwaves planar circuits is proposed with an original method based on the Waves Concept Iterative Process (WCIP). It consists in the development of simulation software based on an iterative method. The iterative method is developed from the fast modal transform on a two-dimensional fast Fourier transform (FFT) algorithm. The method has been applied to the characterization and the modeling of patch antennas with notches in microstrip and coplanar technology and the quarter wavelength directive coupler. The obtained results are very powerful and successfully compared to others methods in term of time and reliability of convergence and particularly the accuracy of the results obtained in comparison with previous works.

Miniaturized Microcantilever-based RF Microwave Probes Using MEMS Technologies

In this study, miniaturized microwave cantilever-based probes - using silicon-on-insulator (SOI) technology - are proposed for the on-chip electrical characterization of nanodevices. In contrast with conventional on-wafer probing structures, small pad dimensions around 1μm2 associated with a 4.5μm-pitch are demonstrated. The probe structure, designed in coplanar technology, is optimized in order to ensure a low contact resistance. The fabrication steps of the probe structures have been developed by means of microelectromechanical systems (MEMS) technology. Measurement performance up to 50GHz exhibit return loss better than -15dB and insertion loss lower than -2.5dB.

A high-gain high-power amplifier MMIC for V-band applications using 100 nm AlGaN/GaN dual-gate HEMTs

In this paper we present the design and realization of a high-power amplifier in grounded coplanar transmission line technology using AlGaN/GaN dual-gate High electron mobility transistors (HEMTs) with a gate-length of 100 nm to achieve a high gain per stage and high output power. A large-signal model was extracted for the dual-gate HEMT based on the state-space approach. For the fabricated dual-stage amplifier a continuous-wave saturatedoutput power of up to 24.8 dBm (0.84 W/mm) was measured at 63 GHz for 20 V drain bias. A small-signal gain of more than 20 dB was achieved between 56 and 65 GHz.

Cryogenic Low-Noise mHEMT-Based MMIC Amplifiers for 4–12 GHz Band

Two broadband very low-noise amplifiers operating in the frequency range from 4 to 12 GHz at cryogenic temperature are presented. The amplifier circuits have been developed using a 100 nm gate length InAlAs/InGaAs metamorphic high electron mobility transistor (mHEMT) technology. The three-stage amplifiers are monolithic microwave integrated circuit (MMIC) chips manufactured in coplanar technology. At cryogenic temperature the first MMIC amplifier achieved a linear gain of 22 dB and an average noise temperature of 11.6 K with a power dissipation of 41 mW. The second MMIC amplifier, with external input matching network, exhibited a gain of 26 dB, and an excellent average noise temperature of 8.1 K with a power dissipation of 12 mW. Both LNA units demonstrate broad bandwidth, high gain, low noise temperature, and compact chip size. The results obtained prove that mHEMT technology is suitable for applications in large instantaneous bandwidth cryogenic receivers for radio astronomy applications.

Realization of a Calculable RF Power Standard in Coplanar Technology on Alumina Substrate

This paper presents the first efforts toward a calculable power standard in the RF domain based on a modeling approach. Consequently, it could be possible to theoretically determine the input reflection coefficient and the efficiency of the power detector. We simulated and realized a coplanar thermistor mount prototype in the 50-MHz-8-GHz frequency range whose performance has been validated by measurements. The maximum deviations between simulated and measured values do not exceed 0.06 for the reflection coefficient. The mean relative error between the measured and computed efficiency is about 1.2% over the whole frequency band. Finally, the input reflection coefficient is less than -15 dB and the efficiency is greater than 0.90 in the 50-MHz-7-GHz frequency range.

Synthesis of compact and highly selective filters via metamaterial-inspired coplanar waveguide line technologies

In this study, two split ring resonator-based coplanar waveguide cells operating in C-band are studied. Particularly, the lines have been loaded with double shunt strips or series gaps. The use of double strips allows controlling the electric plasma frequency, and at the same time permits one to have a good excitation of the resonators. On the other hand, the employment of double series gaps provides a right-handed behaviour, contrary to conventional metamaterial structures for which a backward propagation is obtained. Several parametric studies show the possibility to significantly increase the selectivity, and in particular the possibility to have an effective control on the out-of-band rejection levels by means of the loading elements characteristics. In a second stage, enhanced out-of-band rejection properties have been obtained by the use of cascaded basic cells and rigorous optimization processes. As a consequence, the proposed filters can be foreseen for practical applications relying on the trade-off found between selectivity, insertion losses and out-of-band rejection.

UWB binomial curved monopole with binomial curved ground plane

AbstractThe design of a new ultra‐wideband (UWB) coplanar waveguide antenna is presented. The proposed antenna is a printed‐circuit monopole using coplanar technology. The radiating element is a modified monopole with an optimal shape based on a binomial function. The ground plane is also designed with the same law. Different orders of this binomial function are considered. The antenna shape and dimensions are optimized to achieve an UWB bandwidth operation covering the frequency range from 3.1 to 10.6 GHz. A prototype of the designed antenna was fabricated and measured. Obtained results show that the proposed antenna provides omnidirectional elevation pattern across the operating band. Results provided by simulations and measurements are presented and discussed; they show a good agreement. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 2308–2313, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24645

Application of wave concept iterative process to analyse microwave planar circuits

In the present work, the modeling of high frequencies planar circuits is proposed with an original iterative method based on the concept of waves. It consists in the development of simulation software based on an iterative method. The iterative method is developed from the fast modal transform on a two-dimensional fast Fourier transform algorithm. The method has been applied to the characterization and the modeling of patch antennas with notches in microstrip and coplanar technology and the quarter wavelength directive coupler. The obtained results are very satisfactory particularly in the reduction of the simulation time and the precision of the results in comparison with the literature.

Coplanar UWB antenna with increased suppression characteristics

AbstractThe improved band‐notch capability of an ultra‐wideband antenna in coplanar technology is demonstrated. The printed‐circuit element includes not only a slot to attenuate narrowband services but also a coplanar‐waveguide filter in the feeding line to aid attenuation level and bandwidth in the same frequency range. The input match of the antenna increases from around 10 dB (VSWR = 2) in the UWB range to −1.29 dB (VSWR = 13.5) in the suppression band. The radiation patterns of the antenna remain largely uninfluenced by the bandstop measures added to the antenna. The performance is validated by comparison with different commercial full‐wave field solvers. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3111–3114, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23881

Superconducting Delay Lines

Many superconducting delay line structures have been implemented, using various technologies. In this paper, a comprehensive overview of these delay-lines is given. The advantages and disadvantages of using different planar technologies for the construction of superconducting delay lines are discussed in greater detail. It was revealed that most of the superconducting delay line structures reported can be categorized into a few popular structures, namely meander line, double-spiral line, and unit-cell structures. Our recently published novel double-spiral meander delay line structure is also included for comparison. The new structure was implemented using both microstrip and coplanar technologies and the performance is superior compared to any delay lines reported previously. Besides, investigated meander and fractal delay line structures were also reported, with theoretical analysis in frequency and time domains.

The integration of thin-film microstrip and coplanar technologies for reduced-size MMICs

This paper proposes the integration of coplanar waveguide (CPW) and thin-film microstrip transmission lines to achieve size reduction of monolithic microwave integrated circuits (MMICs). The proposed structures take advantage of the multilevel metallization processes offered in MMIC technology. A very compact 90/spl deg/ CPW branchline coupler, operating at 44 GHz, is used to illustrate the technique. In comparison with conventional hybrid couplers, this coupler offers lower insertion loss and significantly smaller dimensions. The area of the coupler is approximately 65% of a conventional coupler. This paper also presents a family of novel series/shunt matching stub structures based on the CPW/thin-film microstrip combination. The technique allows a reduction in the length of matching stubs of approximately 50% by collocating multiple stubs together. Simulated and experimental results are presented in support of the novel structures.

Theoretical and experimental study of compensated bridges in coplanar technology: Flexibility of the compensation method

AbstractThis paper describes a systematic study of compensated bridges in coplanar technology. If bridges are necessary for filtering the parasitic coupled slot‐line mode excited by coplanar discontinuities, they modify the electrical characteristics associated with the fundamental even mode. Based on a low‐pass filter approach, a very simple technique is used to compensate for this parasitic effect. Here, emphasis is placed on the flexibility of this compensation technique, which allows us to reduce the technological constraints. Several solutions based on this approach are presented in the case of transmission lines, discontinuities such as tee junctions, and classical distributed bandpass filters. This study is valid for air bridges in classical coplanar technology, as well as for integrated dielectric bridges in multilayer coplanar technology. The concepts developed in this paper are illustrated theoretically and experimentally on multilayer devices over the 1–50 GHz frequency band. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 32: 402–408, 2002.

Monolithic coplanar transmission lines loaded by heterostructure barrier varactors for a 60 GHz tripler

Nonlinear transmission lines (NLTLs) loaded by InP-based heterostructure barrier varactors (HBVs) have been fabricated in a monolithic coplanar technology for the first time. The devices were designed for a tripler with a 60 GHz; output frequency. The single HBV diodes, fabricated in a dual barrier scheme, exhibit a capacitance ratio of 6:1, a normalized capacitance of 1.4 fF//spl mu/m/sup 2/ and a voltage breakdown in excess of 10 V. Under moderate pumping (20 dBm), a tripling operation with 30% bandwidth was demonstrated with unsaturated conversion efficiency (1%) for a eight-HBV prototype.