Grounded Coplanar Waveguide Research Articles

Monolithic ceramic waveguide filter using a transition between GCPW feed and ceramic waveguide for 28 GHz

AbstractIn this letter, a mm‐wave monolithic ceramic waveguide filter using a transition between a grounded coplanar waveguide (GCPW) feed and a ceramic waveguide has been proposed. The published studies on monolithic ceramic waveguide filters with wideband properties for the mm‐wave are lacking. A desired external quality factor, satisfying wide bandwidth, is achieved using both inductive and capacitive couplings in the transition. The inductive coupling is realized with a waveguide's hole directly connected to the microstrip line probe of the GCPW. The capacitive coupling is employed with the slots of both GCPW and ceramic waveguide, which are placed facing each other. Adopting the presented transition, the inline monolithic ceramic waveguide filter for a fourth‐order Chebyshev response was designed. The fabricated filter provided the insertion and return losses of lower than 1.2 dB and higher than 10 dB, respectively, at frequencies from 26.43 to 29.76 GHz, with a fractional bandwidth of 11.85%.

A D-Band Self-Packaged Low Loss Grounded Coplanar Waveguide to Rectangular Waveguide Transition With Silicon-Based Air Cavity-Backed Structure

A D-Band Self-Packaged Low Loss Grounded Coplanar Waveguide to Rectangular Waveguide Transition With Silicon-Based Air Cavity-Backed Structure

Device for detection of activity-dependent changes in neural spheroids at MHz and GHz frequencies

Intracellular processes triggered by neural activity include changes in ionic concentrations, protein release, and synaptic vesicle cycling. These processes play significant roles in neurological disorders. The beneficial effects of brain stimulation may also be mediated through intracellular changes. There is a lack of label-free techniques for monitoring activity-dependent intracellular changes. Electromagnetic (EM) waves at frequencies larger than 1x106 Hz (1 MHz) were previously used to probe intracellular contents of cells, as cell membrane becomes “invisible” at this frequency range. EM waves interact with membranes of intracellular organelles, proteins, and water in the MHz – GHz range. In this work, we developed a device for probing the interaction between active neurons’ intracellular contents and EM waves. The device used an array of grounded coplanar waveguides (GCPWs) to deliver EM waves to a three-dimensional (3D) spheroid of rat cortical neurons. Neural activity was evoked using optogenetics, with synchronous detection of propagation of EM waves. Broadband measurements were conducted in the MHz-GHz range to track changes in transmission coefficients. Neuronal activity was found to reversibly alter EM wave transmission. Pharmacological suppression of neuronal activity abolished changes in transmission. Time constants of changes in transmission were in the seconds – tens of seconds range, suggesting the presence of relatively slow, activity-dependent intracellular processes. This study provides the first evidence that EM transmission through neuronal tissue is activity-dependent in MHz – GHz range. Device developed in this work may find future applications in studies of the mechanisms of neurological disorders and the development of new therapies.

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

A vertical transition for suspended line with two transition modes

In this article, we propose a substrate-integrated suspended line (SISL) vertical transition for chip packaging. The transition structure supports both counter-directional and co-directional modes for single-module packaging and vertical integration, respectively. Furthermore, the incorporation of an electromagnetic band gap (EBG) reduces the demands on substrate electrical contact and simplifies the assembly process. A transition structure was designed to convert SISL to a grounded coplanar waveguide (GCPW) to facilitate measurement. The overall structure can be implemented using cost-effective printed circuit board (PCB) technology. Two prototypes of this transition were designed and fabricated. In the frequency range of 12–18 GHz, corresponding to a fractional bandwidth of 40%, the measured return loss is better than 12 dB, while the insertion loss remains consistently below 2.2 dB.

A GCPW slow‐wave transmission line with improved wavelength reduction technique by adopting capacitor array

AbstractThis letter presents a grounded coplanar waveguide (GCPW) slow‐wave transmission line (SWTL) with an improved wavelength reduction technique by adopting capacitor array. By cross‐interleaving additional capacitors between a signal line and side ground planes, the total capacitance in the capacitor array increases approximately two times compared to the conventional structure, allowing designers to choose a smaller signal conductor's width for higher inductance, thus, improving wavelength reduction performance while preserving the same characteristic impedance. At the 150 GHz frequency of interest, the proposed GCPW SWTL shows approximately 20% and 62.16% reduction in wavelength compared to the reported GCPW SWTL and regular CPW, respectively, with the same characteristic impedance. To prove the effectiveness of the proposed SWTL concept, the proposed GCPW SWTL test patterns are fabricated in a 65 nm CMOS process.

Assessment of Measurement Uncertainty for S-Parameter Measurement Based on Covariance Matrix.

S-parameters are widely used to detail the scattering parameters of radio frequency (RF) components and microwave circuit modules. The vector network analyzer (VNA) is the most commonly used device for measuring S-parameters. Given the multiple frequency points, complex values, and intricate uncertainty propagation involved, accurately assessing the uncertainty of S-parameter measurements is difficult. In this study, we proposed a new method for assessing S-parameter uncertainty based on the covariance matrices, tracing back to the nominal uncertainty of calibration standards. First, we analyzed the relevant theory of uncertainty assessment using covariance matrices and subsequently deduced the mechanism of Type B uncertainty propagating from calibration standards to error model coefficients and S-parameter measurements to evaluate Type B measurement uncertainty. In this study, a novel measurement system was constructed for measuring grounded coplanar waveguides by using a VNA and calibration standards with 8- and 12-error models. Initially, the model assessed the Type B uncertainty of measuring four S-parameters of a grounded coplanar waveguide. Next, the VNA calibrated with the 12-error model was used to conduct multiple repeated measurements to assess the Type A uncertainty of the grounded coplanar waveguide. Finally, the composite uncertainty was constructed, which demonstrated that the proposed method can be used for assessing the uncertainty of S-parameters.

Simultaneous electromagnetic field probing system with Y‐shaped separation detection structure

AbstractSimultaneous electromagnetic field probing system (SEMPS) has been popular in recent years. Herein, a simultaneous electromagnetic field probing system with Y‐shaped separation detection structure (SEMPS Y) is first proposed, in which the electric field probing region and the magnetic field probing region of the probe are separated by completely covering the shield along the loop and adding a pin‐shaped metal wire to capture the electric field, which are not the same as the classical dual probe structure. Combined with the non‐rotating asymmetric calibration method (NRACM), a 4‐port vector network analyser (VNA) and a highly symmetric grounded coplanar waveguide (GCPW) calibrator are used to solve the calibration matrix of the asymmetric SEMPS Y. The high symmetry GCPW calibrator is used to generate the standard electromagnetic field for calibration. The results of standing wave measurements show that the SEMPS Y can achieve ultrawideband electromagnetic field measurement of up to 20 GHz. Based on near‐field scanning measurements, SEMP Y can obtain results consistent with the calculation. In addition, when the probe is rotated 90° to invalidate the H‐field input, the decoupling curves of E‐field and H‐field are measured. Results show that the separation detection structure can effectively solve the cross‐coupling problem.

Highly integrable planar-structured printed circularly polarized antenna for emerging wideband internet of things applications in the millimeter-wave band

This paper proposes a numerically and experimentally validated printed wideband antenna with a planar geometry for Internet of Things (IoT) applications. This design tackles the challenges associated with deploying IoT sensors in remote areas or across extensive geographical regions. The proposed design exploits a coplanar-waveguide-fed modified microstrip line monopole for excitation of circularly polarized waves radiating in the broadside direction. The primary design is based on perturbations of the microstrip line protracted from a grounded coplanar waveguide. The capacitively coupled short rectangular stubs are periodically inserted alternately and excited asymmetrically on each side of the microstrip line parallel to the direction of the electric field vector. The sequential phase excitation of the periodic stubs generates a rectangular-cascaded electric field, which suppresses the stop band at the open end. As a result, the antenna radiates in the broadside direction. The impedance bandwidth of the antenna exceeds 8 GHz in the 28 GHz mm-wave band, i.e., it ranged from 25 to 33.5 GHz. Additionally, an axial ratio below 3 dB is achieved within the operating band from 26 to 33.5 GHz with the alterations of the surface current using straightforward topological adjustments of the physical parameters. The average in-band realized gain of the antenna is 10 dBic when measured in the broadside direction. These results indicate that the proposed design has the potential to improve the connectivity between IoT devices and the constantly varying orientation of satellites by mitigating the polarization mismatch.

Theory vs. Reality: Using Printed Circuit Board Technology for Grounded Coplanar Waveguide at Millimeter-Wave Frequencies: Understanding PCB Technology for Millimeter-Wave Applications

Theory vs. Reality: Using Printed Circuit Board Technology for Grounded Coplanar Waveguide at Millimeter-Wave Frequencies: Understanding PCB Technology for Millimeter-Wave Applications

An Ultra-Compact Surface Plasmon Transmission Line Based on Partially Grounded Coplanar Waveguide

An Ultra-Compact Surface Plasmon Transmission Line Based on Partially Grounded Coplanar Waveguide

High Frequency Mid-Infrared Quantum Cascade Laser Integrated With Grounded Coplanar Waveguide Transmission Line

High Frequency Mid-Infrared Quantum Cascade Laser Integrated With Grounded Coplanar Waveguide Transmission Line

Design of High-Gain Antenna Arrays for Terahertz Applications.

A terahertz band (0.1-10 THz) has the characteristics of rich spectrum resources, high transmission speed, strong penetration, and clear directionality. However, the terahertz signal will suffer serious attenuation and absorption during transmission. Therefore, a terahertz antenna with high gain, high efficiency, and wide bandwidth is an indispensable key component of terahertz wireless systems and has become a research hotspot in the field of antennas. In this paper, a high-gain broadband antenna is presented for terahertz applications. The antenna is a three-layer structure, fed by a grounded coplanar waveguide (GCPW), using polytetrafluoroethylene (PTFE) material as the dielectric substrate, and the metal through-hole of the dielectric substrate forms a substrate-integrated waveguide (SIW) structure. The metal fence structure is introduced to reduce the coupling effect between the radiation patches and increase the radiation bandwidth and gain. The center frequency is 0.6366 THz, the operating bandwidth is 0.61-0.68 THz, the minimum value of the voltage standing wave ratio (VSWR) is 1.00158, and the peak gain is 13.14 dBi. In addition, the performance of the designed antenna with a different isolation structure, the length of the connection line, the height of the substrate, the radius of the through-hole, and the thickness of the patch is also studied.

Field Analysis for Superconducting Grounded Coplanar Waveguide Transmission Lines

Field Analysis for Superconducting Grounded Coplanar Waveguide Transmission Lines

Characterization of Embedded and Thinned RF Chips

This work studies the effect of thinning down chips with transmission line structures for flexible embedding technology. Test chips with 90 Ω grounded coplanar waveguide (GCPW) transmission lines have been designed and manufactured to characterize the high-frequency performance before and after embedding in sheet molding compound (SMC), and thinning down from 300 μm to 20 μm. Molding first technology enables single-die or multiple-die thinning with the embedding material while being held in the exact position, where the subsequent fanout copper (Cu) redistribution layer (RDL) structuring realizes the direct contacts to the embedded chip, followed by semiadditive manufacturing of traces. The embedded and thinned chips are characterized by S-parameter measurements in the frequency range from 20 MHz to 65 GHz using a vector network analyzer (VNA). The results show the feasibility of the examined embedding and thinning processes which are suitable for millimeter wave (mmWave) components as shown by the example of a G-CPW transmission line without degrading its RF performance in terms of characteristic impedance and attenuation.

A comprehensive packaging solution from DC to 113 GHz for InGaAs amplifiers

AbstractThis letter presents the design, fabrication and measurement of a 72 kHz to 113 GHz ultra‐broadband amplifier that includes a direct current (DC)‐blocking functionality. This amplifier module stands out with a high average gain of 12.5 dB in the frequency range from almost DC to 110 GHz. This work not only combines electrical interconnections but also mechanical design considerations, thermal requirements and practical application specific aspects. To ensure a low thermal resistance, the InGaAs amplifier IC is directly mounted on an aluminium submount, applying an advanced gluing concept, and interconnected to an input and output 50 grounded coplanar waveguide by wire bonds with a length of only 135 . To enable convenient usage of the package, 1 mm connectors are utilized. This amplifier module exhibits excellent thermal behaviour and group delay characteristics, making it an ideal choice for use in optical data transmission experiments.

A Large Frequency Ratio Dual-Band Integrated Bandpass Filter Based on MCSICL Structure

In this paper, a dual-band integrated bandpass filter (DI-BPF) based on a mode composite substrate integrated coaxial line (MCSICL) is proposed for a large frequency ratio. The low-frequency bandpass filter is formed by incorporating an SICL line and a gap into the MCSICL, operating in the fundamental mode of the MCSICL. The high-frequency bandpass filter is formed by introducing grounded vias into the MCSICL, operating in the first high-order mode of the MCSICL. To guide the design, the equivalent circuit models of the low- and high-frequency bandpass filters are built. Based on the equivalent circuit models, the DI-BPF is synthesized for a large frequency ratio. The transitions from the DI-BPF to ground coplanar waveguides (GCPWs) are designed for the low- and high-frequency bandpass filters. The DI-BPF with the transitions is fabricated by the printed circuit board (PCB) process. Measurement results indicate a large frequency ratio of 23.16, with the isolation between the low- and high-frequency bandpass filters exceeding 30 dB from dc to 50 GHz.

Suppressing Non-Ideal Resonance in Defected Ground Structure Based on Grounded Coplanar Waveguide

Suppressing Non-Ideal Resonance in Defected Ground Structure Based on Grounded Coplanar Waveguide

Compact Liquid Crystal Polymer Based Tri-Band Flexible Antenna for WLAN/WiMAX/5G Applications

In this paper, a new compact coplanar waveguide (CPW)-fed liquid crystal polymer (LCP) based tri-band antenna is presented and fabricated for Wireless Local Area Network (WLAN), Worldwide Interoperability for Microwave Access (WiMAX) and 5th-Generation (5G) systems. The antenna combines two strips with the main radiation rectangular patch and coplanar waveguide ground. The proposed antenna is printed on a LCP substrate with a thickness of 0.1 mm and has a small overall dimensions of 20mm×32mm×0.1mm. To analyze the characteristics, the antenna is designed and fabricated, and then the performance of the antenna is measured and tested. The measurement results show that the proposed antenna has three operating bandwidths, including 2.38-2.79 GHz, 3.27-4.05 GHz, and 4.80-8.44 GHz. To test the flexibility of the antenna, the antenna is simulated and measured in bent configurations for radii of 10 mm and 50 mm. In addition, the antenna is attached to different parts of the human body to test the integration effect in wearable equipment. The experimental results show that the performance of the antenna remains reliable under bending conditions and that the specific absorption ratio (SAR) value meets the European Union (EU) standard. The proposed antenna shows reasonable gains and good radiation characteristics in the operating bands. The flexible, compact, simple design and multiband performance indicates that the antenna is suitable for integration in flexible electronic devices.

High-Order Resonating Cavity-Backed Slot Antenna Array Based on Contactless Air-Filled Substrate Integrated Waveguide and Transition to Inverted Grounded Coplanar Gap Waveguide

High-Order Resonating Cavity-Backed Slot Antenna Array Based on Contactless Air-Filled Substrate Integrated Waveguide and Transition to Inverted Grounded Coplanar Gap Waveguide