Design Of Coplanar Waveguide Research Articles

Design of an Ultrawideband Air-Filled Grounded Coplanar Waveguide for Near-Field Probe Calibration

Design of an Ultrawideband Air-Filled Grounded Coplanar Waveguide for Near-Field Probe Calibration

Compact CPW-fed Antenna with Controllable WLAN Band-rejection for Microwave Imaging

This work presents the design and experimental validation of a compact frequency reconfigurable coplanar waveguide (CPW)-fed ultra-wideband (UWB) antenna with a capability to on-demand reject WLAN frequencies within the range of 5.15 GHz to 5.85 GHz, specifically tailored for applications in microwave imaging. The design and experimental results are presented and discussed. The bandwidth enhancement is obtained by using T-shaped slots between the feedline and the ground plane of the antenna, and the WLAN band is rejected by using an open loop resonator (OLR) placed on the antenna backside. Switching between UWB with and without WLAN band-notched modes is performed using a PIN diode and a bias circuit. The simulation results corroborate well with the experimental data and clearly showed an interesting frequency reconfigurable behavior for use in microwave imaging applications. An antenna performance simulation and analysis model is presented for breast tumor detection, and the tumor effect has been noticed for both operating modes of the antenna.

Impedance-matched coplanar-waveguide metal-powder low-pass filters for cryogenic applications.

We developed impedance-matched metal-powder low-pass filters based on coplanar waveguide design and characterized them at room temperature and 77.4K. The coplanar waveguide metal-powder (CPW-MP) filters have a return loss better than 9.8 dB at frequencies up to 10GHz at 77.4K. We find that the filter attenuation per length scales linearly with frequency from 29 to 220 dB/m within the 1-5GHz frequency range at 77.4K, achieving the total attenuation above 100 dB for the 1 m-long CPW-MP filter at frequencies above 2GHz. The CPW-MP filter integrated with the multipole LC filter demonstrates the low cut-off frequency, the attenuation above 100 dB in the stop band, and the high roll-off of 590 dB per decade. The proposed CPW-MP filter is easy to fabricate, has very good thermal-shock resistance, is flexible for integration with other types of low-pass filters, delivers the same performance as classical cryogenic filters, is more compact compared to 50Ω coax cables with the same type of lossy dielectric, and provides ample opportunities for further miniaturization.

Study on measurement capability of probe-backside reflection method for evaluation of dielectric materials

Abstract This study clarifies the measurement capability of the probe-backside reflection (PBR) method for the evaluation of dielectric materials. Because the PBR method requires the preparation of a coplanar waveguide (CPW) on a material-under-test (MUT), the measurement capability is limited not only by the dielectric properties of the MUT but also by the limitations in the CPW design. In this study, the measurement capability of the PBR method was estimated to be limited up to 15 for the dielectric permittivity, and from 3 × 10-3 to 2 × 10-1 for the dielectric loss tangent, in the frequency range up to 300 GHz.

Reliability of VO textsubscript 2-Based mmWave Switches Under 100 Million Thermal Cycles

We report the lifetime investigations of the reversible phase transition vanadium dioxide (VO2) thin film switches integrated with coplanar waveguide (CPW) under fast and direct thermal cycling. We observe that after 100 million thermal cycles, there is no degradation in the performance of VO2 shunt switches operating at 35 – 45 GHz. S11 reflection coefficient as well as S21 transmission measurements (verified independently at both activated and inactivated states) show no statistical difference in port-to-port coupling of the VO2 switch as a function of a cycle number. This study is enabled by the integration of Joule heaters on chip at a close proximity to a shunt VO2 switch and a metallic CPW transmission line. Full-wave electromagnetic and multiphysics electrothermal finite element simulations are conducted to analyze the feasibility of the CPW design and the required time and power for thermal cycling. On-wafer mmWave measurements are carried out on the test vehicle after each thermal cycling phase.

New Design of a Compact 1×2 Super UWB-MIMO Antenna for Polarization Diversity

This paper proposes a new design of compact coplanar waveguide (CPW) fed -super ultra-wideband (S-UWB) MIMO antenna with a bandwidth of 3.6 to 40 GHz. The proposed antenna is composed of two orthogonal sector-shape monopoles (SSM) antenna elements to perform polarization diversity. In addition, a matched L-shaped common ground element is attached for more efficient coupling. The FR-4 substrate of the structure with a size of 23 × 45 × 1.6 mm3 and a dielectric constant of 4.3 is considered. The proposed design is simulated by using CST Microwave Studio commercial software. The simulation shows that the antenna has low mutual coupling (|S21| < -20 dB) with |S11|<−10 dB, ranging from 3.6 to 40 GHz. Envelope correlation coefficient (ECC) is less than 0.008, diversity gain (DG) is more than 9.99, mean effective gain (MEG) is below – 3 dB, and total active reflection coefficient (TARC) is less than -6 dB over the whole response band is reported. The proposed MIMO antenna is expected efficiently cover the broadest range of frequencies for contemporary communications applications.

Optimization and Design of Passive Link with Single Channel 25 Gbps Based on High-Speed Backplane

In recent years, with the development of the communication industry, the need to use Ethernet switches to transmit big data has become more urgent, and its protocol standards are iterating towards higher return loss, wider bandwidth, lower impedance fluctuations and insertion loss. Based on the research of high-speed backplane with a single channel 25 Gbps transmission rate, a novel double grounded planar strip coplanar waveguide design is presented, which significantly improved return loss to 20 dB and reduced insertion loss, which meet the loss standard of 100GBASE-KR4. The resonant cavity model of transmission line reference plane is improved by introducing vias and the parameters of vias in the reference plane are studied to reduce the impact of resonance, which improved the transmission −1 dB bandwidth to 60 GHz. Based on equivalent circuit analysis of differential vias’ joint reverse pad, the parameters related to the differential vias are studied, the impedance fluctuation is reduced to 100 ± 3 Ω, which is 70% better than the impedance fluctuation standard (100 ± 10 Ω) of 100GBASE-KR4. After optimizing the mathematical model of strip coplanar waveguide, reference plane and differential vias, we built a simulation model of the backplane passive link which met the 100GBASE-KR4 backplane Ethernet specification. In the actual test, it was found that the optimized model can improve the link performance.

A terahertz on-chip InP-based power combiner designed using coupled-grounded coplanar waveguide lines* *Project supported in part by the National Natural Science Foundation of China (Grant No. 61871072).

This article presents the design and performance of a terahertz on-chip coupled-grounded coplanar waveguide (GCPW) power combiner using a 50μm-thick InP process. The proposed topology uses two coupled-GCPW lines at the end of the input port to substitute two quarter-wavelength GCPW lines,which is different from the conventional Wilkinson power combiner and canavailably minimize the coverage area. According to the results obtained, forthe frequency range of 210–250z, the insertion losses for each two-waycombiner and four-way combiner were lower than 1.05 dB and 1.35 dB,respectively, and the in-band return losses were better than 11 dB. Moreover,the proposed on-chip GCPW-based combiners achieved a compromise in low-loss, broadband, and small-size, which can find wide applications in terahertz bands, such as power amplifiers and signal distribution networks.

Dual-band MIMO coplanar waveguide-fed-slot antenna for 5G communications

This paper presents two new designs of MIMO dual band coplanar waveguide (CPW)-fed-slot antennas operating in the 5G frequency band (28 and 38 GHz). The first antenna is an XX MIMO antenna and the second antenna is an XY MIMO antenna. Simulated results for the S-parameters are presented for the two antennas using HFSS. Measured results are also presented for the return loss and gain with both results showing good agreement. The current distribution, group delay, envelope correlation coefficients (ECC), and diversity gain, are also presented for both antennas. The two antennas are fabricated on a substrate having dielectric constant εr = 10.7 and substrate thickness 0.635 mm. The size of the antenna is 4.4 mm x 4.1 mm x 0.635 mm.

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.

Characterizing dielectric properties of ultra-thin films using superconducting coplanar microwave resonators.

We present an experimental approach for cryogenic dielectric measurements on ultrathin insulating films. Based on a coplanar microwave waveguide design, we implement superconducting quarter-wave resonators with inductive coupling, which allows us to determine the real part ε1 of the dielectric function at gigahertz frequencies and sample thicknesses down to a few nanometers. We perform simulations to optimize resonator coupling and sensitivity, and we demonstrate the possibility to quantify ε1 with a conformal mapping technique in a wide sample-thickness and ε1-regime. Experimentally, we determine ε1 for various thin-film samples (photoresist, MgF2, and SiO2) in the thickness regime of nanometer up to micrometer. We find good correspondence with nominative values, and we identify the precision of the film thickness as our predominant error source. Additionally, we present a temperature-dependent measurement for a SrTiO3 bulk sample, using an in situ reference method to compensate for the temperature dependence of the superconducting resonator properties.

Modeling of Multilayer MMIC Coplanar Waveguide Low Pass Filter for Cellular Application

In the early development of Monolithic Microwave Integrated Circuit (MMIC) technology, most of the components use Microstrip structure. In order to connect the active components to the ground in the Microstrip design is limited by the thickness of the substrate to avoid circuit performance degradation due to vertical coupling. Thus it can be said that the Microstrip is not the primary choice of design in operating components at microwave and millimeter wave frequencies. The Coplanar Waveguide (CPW) design technique was proposed as an alternative to the Microstrip structure for MMIC components. With CPW design technique, it generates components and circuits which are cost-effective and allow miniaturization of components in MMIC environment. In this paper, CPW Low Pass Filter (LPF) electromagnetic modeling has been demonstrated based on multilayer MMIC technology for the 2,100 MHz mobile application. The LPF CPW specification has been modeled with the substrate of GaAS (εr=12.9) and Polymide (ϵr=3.7). The thickness of GaAS substrate and Polyimide dielectric is 600 micron and 2.5 micron respectively for each layer.

CPW-Fed Planar Ultra-Wideband Notched Antenna at Wimax Frequency

Abstract This paper presents a new design of compact CoPlanar Waveguide (CPW)-fed patch antenna for Ultra Wide Band (UWB) operation with a radiating element presented of size 20mm x 20mm x 1.6 mm using FR4 lossy substrate with a band rejection (Voltage Standing Wave Ratio VSWR > 2) achieved at 3.38–3.85 GHz to reject WiMAX band. This antenna consists of a radiating patch with partial ground above the substrate to increase the band width. A C-shaped slot is etched on the patch to provide frequency notch to avoid interference of UWB band with the existing systems. This antenna has an operating frequency from 3.5 to 18 GHz. In this paper, the variations of frequency notches characteristics are discussed by varying the length and width of the slot. The performance of the suggested antenna is investigated by using CST microwave studio.

Design and performance analysis of broadband rectenna for an efficient RF energy harvesting application

This article proposes the design of coplanar waveguide (CPW) fed broadband rectenna for radio frequency (RF) energy harvesting application. The rectenna is designed to operate in the industrial, scientific, and medical (ISM) frequency band of 5.8 GHz. For designing the proposed rectenna, polytetrafluoroethylene (PTFE) dielectric material was used to design, fabricate the CPW fed slot antenna. It was observed that the proposed antenna exhibits the |S11| of −23.43 dB and achieves the peak antenna gain of 8.56 dBi at 5.8 GHz. Secondly, the CPW fed rectifier circuit which comprises of the matching circuit, rectifying unit, and filter was designed. The measured results showed that the |S11| of −19 dB and it was perfectly matched with 50 Ω impedance. Finally, the rectenna was designed by integration of antenna with rectifier circuit. The simulated results showed the maximum RF to direct current (DC) conversion efficiency and the output DC voltage of 88% and 445 mV at the load resistance of 1 kΩ. The measured results show the maximum RF to DC conversion efficiency of 73.4% with the output DC voltage of 540 mV at the load resistance of 1 kΩ.

Design of UWB monopole antenna with dual notched band characteristics by using π-shaped slot and EBG resonator

In this paper, we propose the design of coplanar waveguide (CPW) ultra-wideband (UWB) dual notched band monopole antenna with a π-shaped slot and EBG is proposed. The designed antenna produces an impedance bandwidth of 2.7–11.7 GHz (VSWR < 2), except with 3.4 GHz (3.3–3.7 GHz) for S-band WiMAX application and 6.9 GHz (6.5–7.2 GHz) for C-band IEEE INSAT applications. Here, the lower and upper notches are realized by proposing a π-shaped slot on the radiating element and an electromagnetic bandgap structure as a resonator integrated on either side of the ground plane. Meanwhile, the impedance over a frequency range and current distribution are also plotted for the proposed design. The antenna prototype is fabricated and characterized experimentally for validation purpose. Fair matching is observed among the simulated and measured results.

CPW based Band Pass Filter Using DGS for ISM Band Applications

The design and simulation of coplanar waveguide (CPW) bandpass filter (BPF) has been described in this paper. It mainly focuses on Defected Ground Structure (DGS), where U-shaped DGS with open stub in transmission line has been introduced. By etching the DGS pattern in ground and transmission will change the distribution of inductance and capacitance to produce filtering effect. This paper also discusses about the influence of geometrical parameter l for the improvement in the frequency response of bandpass filter. As increasing the dimension of the geometric parameter l shift the center frequency to the higher frequencies. This filter offers a bandwidth of 1.65 GHz with passband ranging from 2.1 GHz to 3.75 GHz with a stopband rejection is about -28 dB.

Advanced multilayer thick‐film technology and TFMS, CPW, and SIW up to 180 GHz for cost‐effective ceramic‐based circuits and modules

This study presents the design, accurate characterisation, and performance comparison for multilayer thin-film microstrip (TFMS), coplanar waveguide (CPW), and substrate integrated waveguides (SIW) lines and interconnects for various transverse dimensions, which are fabricated on thin dielectric layers, using advanced ceramic-based photoimageable thick-film technology. The influence of ground-plane width on multilayer finite-ground planar transmission lines (TFMS and CPW) and the influence of cavity dimensions on SIW have been experimentally studied. This includes the variation of characteristic impedance and attenuation with normalised ground-/cavity-width and extending frequency to beyond 110 GHz (180 GHz, for SIW). Contrary to conventional fence-post, metal-filled trenches have been used for SIW, showing high performance (loss of 0.2 dB/mm at 110 GHz, even for a thin dielectric) and suitable for operation beyond 180 GHz, the highest frequency reported for off-chip integration in MCMs. Further, for the first time, comprehensive comparative performances of traditional microstrip, TFMS, CPW, and SIW, in circuit/system design perspective, have been presented for enabling proper selection of transmission media and interconnect with optimum transverse/ground width, and development of compact and high performance millimetre-wave multichip module front-ends economically.

Multi-Reconfigurable Band-Notched Coplanar Waveguide-Fed Slot Antenna

This paper proposes an antenna design concept to achieve a multi-reconfigurable band-notch antenna by using a set of microswitches. The proposed idea was proved by the design of the coplanar waveguide (CPW)-fed slot antenna. The sample design gives a wideband antenna the impedance bandwidth of which covers the frequency ranged from 1.9 GHz to 6.55 GHz. The antenna could be configured to work either in single-band mode or in one of the defined dual-band modes.

A New CPW-fed Patch Antenna for UWB Applications

In this paper, the design and analysis of a compact size coplanar waveguide (CPW)-fed antenna for ultrawideband (UWB) applications is presented. The antenna has a compact size of 20×20×1.1 .5 .mm and provides a good impedance matching over the entire bandwidth of 3.2–14.3 GHz. The characteristics parameters, i.e. return loss, VSWR and radiation pattern, are analyzed using HFSS 11.0 software.

Novel Conception of a Tunable RF MEMS Resonator

This paper presents a new monolithic microwave integrated circuit (MMIC) based on coplanar waveguide (CPW) design for a tunable resonator based on RF MEMS. This RF structure, which can be used for system on chip (SOC), is constituted with MEMS Bridge placed between two meander inductors and the tenability is controlled by a variable applied DC voltage. Moreover, this device presents a compactness characteristic and the possibility to operate at high frequencies. The resonant frequency and the bandwidth can be changed easily by changing the bridge gap of the RF MEMS. The numerical simulations of this novel structure of a tunable RF MEMS resonator were performed with the electromagnetic solvers CST MWS (Computer simulation Technology Microwave Studio) and validated by the more accurate electromagnetic solver HFSS (High Frequency Structural Simulator). The simulation results, for three different spacing of the bridge gap, show that the tunable frequency band are between 10 and 40 GHz with the two electromagnetic solvers and exhibiting three resonant frequencies (21, 23.1 and 24.6 GHz).The simulation results of the return loss using CST achieves 29 dB with an insertion loss less than 1 dB; However, the HFSS simulation shows similar performance in the resonant frequencies and in the bandwidth giving better results in terms of the return loss (about 35dB instead of 29 dB) and showing a good adaptation.