Showing papers on "Coplanar waveguide published in 2014"

Broadband and high-efficiency conversion from guided waves to spoof surface plasmon polaritons

Abstract: The conversion from spatial propagating waves to surface plasmon polaritons (SPPs) has been well studied, and shown to be very efficient by using gradient-index metasurfaces. However, feeding energies into and extracting signals from functional plasmonic devices or circuits through transmission lines require the efficient conversion between SPPs and guided waves, which has not been reported, to the best of our knowledge. In this paper, a smooth bridge between the conventional coplanar waveguide (CPW) with 50 Ω impedance and plasmonic waveguide (e.g., an ultrathin corrugated metallic strip) has been proposed in the microwave frequency, which converts the guided waves to spoof SPPs with high efficiency in broadband. A matching transition has been proposed and designed, which is constructed by gradient corrugations and flaring ground, to match both the momentum and impedance of CPW and the plasmonic waveguide. Simulated and measured results on the transmission coefficients and near-filed distributions show excellent transmission efficiency from CPW to a plasmonic waveguide to CPW in a wide frequency band. The high-efficiency and broadband conversion between SPPs and guided waves opens up a new avenue for advanced conventional plasmonic integrated functional devices and circuits.

Novel Empty Substrate Integrated Waveguide for High-Performance Microwave Integrated Circuits

Abstract: Over the last years, a great number of substrate integrated circuits has been developed. These new circuits are a compromise between the advantages of classical waveguide technologies, such as high quality factor and low losses, and the advantages of planar circuits, such as low cost and easy compact integration. Although their quality factor and losses are better than for planar circuits, these characteristics are worse than in the case of waveguides, mainly due to the presence of the dielectric substrate. In order to improve the performance of the integrated circuits, a new methodology for manufacturing empty waveguides, without a dielectric substrate, but at the same time completely integrated in a planar substrate, is proposed in this work. A wideband transition with return losses greater than 20 dB in the whole bandwith of the waveguide allows the integration of the empty waveguide into the planar substrate so that the waveguide can be directly accessed with a microstrip line. Therefore, a microwave circuit integrated in a planar substrate, but at the same time with a very high quality factor (measured quality factor is 4.5 times higher than for the same filter in the substrate integrated waveguide), and very low losses is successfully achieved.

Angular Displacement and Velocity Sensors Based on Electric-LC (ELC) Loaded Microstrip Lines

Abstract: Planar microwave angular displacement and angular velocity sensors implemented in microstrip technology are proposed. The transducer element is a circularly shaped divider/combiner, whereas the sensing element is an electric-LC resonator, attached to the rotating object and magnetically coupled to the circular (active) region of the transducer. The angular variables are measured by inspection of the transmission characteristics, which are modulated by the magnetic coupling between the resonator and the divider/combiner. The degree of coupling is hence sensitive to the angular position of the resonator. As compared with coplanar waveguide angular displacement and velocity sensors, the proposed microstrip sensors do not require air bridges, and the ground plane provides backside isolation.

Characterization and reduction of microfabrication-induced decoherence in superconducting quantum circuits

Abstract: Many superconducting qubits are highly sensitive to dielectric loss, making the fabrication of coherent quantum circuits challenging. To elucidate this issue, we characterize the interfaces and surfaces of superconducting coplanar waveguide resonators and study the associated microwave loss. We show that contamination induced by traditional qubit lift-off processing is particularly detrimental to quality factors without proper substrate cleaning, while roughness plays at most a small role. Aggressive surface treatment is shown to damage the crystalline substrate and degrade resonator quality. We also introduce methods to characterize and remove ultra-thin resist residue, providing a way to quantify and minimize remnant sources of loss on device surfaces.

Single-Layer Differential CPW-Fed Notch-Band Tapered-Slot UWB Antenna

Abstract: A single-layer differential coplanar waveguide (CPW)-fed notch-band tapered-slot ultrawideband (UWB) antenna is proposed in this letter. In order to achieve the sharp and controllable notch-band characteristic, one pair of half-wavelength stubs and slits are introduced inside the tapered slot and in the circular patches, respectively. Compared to a single-ended CPW-fed UWB antenna, due to adopting the differential feeding structure, the proposed antenna has lower cross polarization. Since all of the structures are printed on the same layer of the substrate, it can be fabricated easily and very suitable to be integrated with RF front-end circuits. The measured -10-dB impedance bandwidth is 126% (from 2.78 to 12.3 GHz), along with a sharp notch band from 5.2 to 6.0 GHz. Good agreement is achieved between the measured results and simulated results.

An MIMO Rectangular Dielectric Resonator Antenna for 4G Applications

Abstract: A multiple-input-multiple-output (MIMO) rectangular dielectric resonator antenna (RDRA) for 2.6-GHz Long Term Evolution (LTE) applications is investigated and presented. Two orthogonal modes of the RDRA are excited by using two different feed mechanisms: coplanar waveguide (CPW) and coaxial probe. The measured impedance bandwidth for port 1 and port 2 is 47% (2.09-3.38 GHz) and 25% (2.40-3.09 GHz), respectively. The measured correlation coefficient is 0.03 with nearly 10 dB diversity gain at frequency 2.6 GHz. The MIMO RDRA gives isolation of above 20 dB over the operating frequency. The gain of 4.97 dBi is obtained for port 1 and 4.51 dBi for port 2 at 2.6 GHz. The S-parameters, isolation, gain, correlation coefficient, and diversity gain of the MIMO RDRA are studied, and reasonable agreement between the measured and simulated results is observed .

Development of a Broadband NbTiN Traveling Wave Parametric Amplifier for MKID Readout

Abstract: The sensitivity of microwave kinetic inductance detectors (MKIDs) using dissipation readout is limited by the noise temperature of the cryogenic amplifier, usually a HEMT with $$T_n \sim $$ 5 K. A lower noise amplifier is required to improve NEP and reach the photon noise limit at millimeter wavelengths. Eom et al. have proposed a kinetic inductance traveling wave (KIT) parametric amplifier (also called the dispersion-engineered travelling wave kinetic inductance parametric amplifier) that utilizes the nonlinearity with very low dissipation of NbTiN. This amplifier has the promise to achieve quantum limited noise, broad bandwidth, and high dynamic range, all of which are required for ideal MKID dissipation readout. We have designed a KIT amplifier which consists of a 2.2 m long coplanar waveguide transmission line fabricated in a double spiral format, with periodic loadings and impedance transformers at the input/output ports on a 2 by 2 cm Si chip. The design was fabricated with 20 nm NbTiN films. The device has shown over 10 dB of gain from 4 to 11 GHz. We have found the maximum gain is limited by abrupt breakdown at defects in the transmission line in the devices. By cascading two devices, more than 20 dB of gain was achieved from 4.5 to 12.5 GHz, with a peak of $$\sim $$ 27 dB.

Characterization and reduction of microfabrication-induced decoherence in superconducting quantum circuits

Abstract: Many superconducting qubits are highly sensitive to dielectric loss, making the fabrication of coherent quantum circuits challenging. To elucidate this issue, we characterize the interfaces and surfaces of superconducting coplanar waveguide resonators and study the associated microwave loss. We show that contamination induced by traditional qubit lift-off processing is particularly detrimental to quality factors without proper substrate cleaning, while roughness plays at most a small role. Aggressive surface treatment is shown to damage the crystalline substrate and degrade resonator quality. We also introduce methods to characterize and remove ultra-thin resist residue, providing a way to quantify and minimize remnant sources of loss on device surfaces.

Fast, low-power manipulation of spin ensembles in superconducting microresonators

Abstract: We demonstrate the use of high-Q superconducting coplanar waveguide (CPW) microresonators to perform rapid manipulations on a randomly distributed spin ensemble using very low microwave power (400 nW). This power is compatible with dilution refrigerators, making microwave manipulation of spin ensembles feasible for quantum computing applications. We also describe the use of adiabatic microwave pulses to overcome microwave magnetic field (B1) inhomogeneities inherent to CPW resonators. This allows for uniform control over a randomly distributed spin ensemble. Sensitivity data are reported showing a single shot (no signal averaging) sensitivity to 107 spins or 3×104spins/Hz with averaging.

Multi-channel composite spoof surface plasmon polaritons propagating along periodically corrugated metallic thin films

Abstract: In this work, we demonstrate that composite spoof surface plasmon polaritons can be excited by coplanar waveguide, which are composed of two different spoof surface plasmon polaritons (SSPPs) modes propagating along a periodically corrugated metallic thin film simultaneously. These two SSPPs correspond to the dominant modes of one-dimensional (1D) periodical hole and groove arrays separately. We have designed and simulated a planar composite plasmonic waveguide in the microwave frequencies, and the simulation results show that the composite plasmonic waveguide can achieve multi-channel signal transmission with good propagation performance. The proposed planar composite plasmonic metamaterial can find potential applications in developing surface wave devices in integrated plasmonic circuits and multi-channel signal transmission systems in the microwave and terahertz frequencies.

An induction method to calculate the complex permeability of soft magnetic films without a reference sample.

Abstract: A new analytical method has been proposed by utilizing an electromagnetic induction principle with a short-circuited microstrip line jig and the complex permeability spectra can be calculated without a known reference sample. The new method using the short-circuited microstrip line can exhibit higher sensitivity and a wider frequency band than coplanar waveguide and pick-up coil. Two magnetic thin films having a good in-plane uniaxial anisotropy are measured by using the induction method. The results show typical complex permeability spectra in good agreement with the theoretical analytical results. The measured permeability values are verified by comparing with the initial susceptibility derived from the sweeping field results. The difference of measured permeability values is less than 5%.

Aerosol jet printing for 3-D multilayer passive microwave circuitry

Abstract: Aerosol jet printed 3-D coplanar waveguides up to 50 GHz are demonstrated in this paper for the first time featuring a multilayer aerosol jet deposition process. The aerosol jet printing utilized in this paper is the first aerosol jet process to demonstrate multilayer deposition with bi-materials and is host substrate independent. The paper provides an insight into the fabrication process, the technology assessment and the characterization of the polyimide as well as the nano silver particles. The printed polyimide could achieve a thickness of 60 μm. The three-dimensional printed transmission lines demonstrated losses of 0.5 dB/mm at 50 GHz. Keywords— 3-D printing, aerosol jet printing, conducting ink, coplanar waveguide, multilayers, RF, silver nano-particle.

A Planar Bandpass Filter Implemented With a Hybrid Structure of Substrate Integrated Waveguide and Coplanar Waveguide

Abstract: In this paper, a novel planar bandpass filter is proposed, designed, and implemented with a hybrid structure of substrate integrated waveguide (SIW) and coplanar waveguide (CPW), which has the advantages of good passband and stopband performance inherited from SIW and miniaturized size accompanying with the CPW. Additional design flexibility is introduced by the hybrid structure for efficiently controlling the mixed electric and magnetic coupling, and then planar bandpass filters with controllable transmission zeros and quasi-elliptic response can be achieved. Several prototypes with single and dual SIW cavities are fabricated. The measured results verified the performance of the proposed planar bandpass filters, such as low passband insertion loss, sharp roll-off characteristics at transition band, etc.

Wideband harmonic rejection filtenna for wireless power transfer

Abstract: Two novel, compact, simple 2nd and 3rd harmonic rejection coplanar waveguide (CPW) feeding mechanisms for a 5.8 GHz rectenna are proposed. Both of them make use of the CPW compact microstrip resonant cell (CMRC). In the first topology, the blockage is realized by a CMRC in combination with a U-slot. In the second topology a pair of strongly coupled CMRCs is optimized. Both these new feeding mechanisms are realized in prototypes and experimentally validated, first in two back-to-back configurations, and then in combination with two CPW fed wideband monopole antennas. The measured antenna return loss at the 2nd and 3rd harmonic is in the order of 0.5 dB and 1.5 dB, respectively, which corresponds to a return loss suppression of about 4 -5 dB compared to a reference monopole antenna. Both antennas reach an 18% 10 dB return loss bandwidth, which is the highest working bandwidth reported in literature for harmonic rejection antennas. Bandwidth could become an issue when wireless power transfer systems would be implemented with a reconfigurable working frequency in order to minimize interference with local telecom equipment.

A Novel Investigation of a Broadband Integrated Inverted-F Antenna Design; Application for Wearable Antenna

Abstract: A general design of the coplanar waveguide excited IIFA, traditionally excited by a Microstrip or coaxial excitation is presented. This coplanar excitation permits the bandwidth improvement (from around 10% to 50%) by the creation of a new resonance on the ground plane. It makes also the antenna more suitable to body area network (BAN) context by facilitating the integration on textile fabric or clothes, and the limitation of body effect at the operation frequency. The antenna principle is analyzed and general designs are presented. As application; a solution of a meandered IIFA integrated on Denim substrate is realized. All results are validated through comparative simulations and measurements.

Wideband Harmonic Rejection Filtenna for Wireless Power Transfer

Abstract: Two novel, compact, simple 2nd and 3rd harmonic rejection coplanar waveguide (CPW) feeding mechanisms for a 5.8 GHz rectenna are proposed. Both of them make use of the CPW compact microstrip resonant cell (CMRC). In the first topology, the blockage is realized by a CMRC in combination with a U-slot. In the second topology a pair of strongly coupled CMRCs is optimized. Both these new feeding mechanisms are realized in prototypes and experimentally validated, first in two back-to-back configurations, and then in combination with two CPW fed wideband monopole antennas. The measured antenna return loss at the 2nd and 3rd harmonic is in the order of 0.5 dB and 1.5 dB, respectively, which corresponds to a return loss suppression of about 4 -5 dB compared to a reference monopole antenna. Both antennas reach an 18% 10 dB return loss bandwidth, which is the highest working bandwidth reported in literature for harmonic rejection antennas. Bandwidth could become an issue when wireless power transfer systems would be implemented with a reconfigurable working frequency in order to minimize interference with local telecom equipment.

Liquid metal actuation-based reversible frequency tunable monopole antenna

Abstract: We report the fabrication and characterization of a reversible resonant frequency tunable antenna based on liquid metal actuation. The antenna is composed of a coplanar waveguide fed monopole stub printed on a copper-clad substrate, and a tunnel-shaped microfluidic channel linked to the printed metal. The gallium-based liquid metal can be injected and withdrawn from the channel in response to an applied air pressure. The gallium-based liquid metal is treated with hydrochloric acid to eliminate the oxide layer, and associated wetting/sticking problems, that arise from exposure to an ambient air environment. Elimination of the oxide layer allows for reliable actuation and repeatable and reversible tuning. By controlling the liquid metal slug on-demand with air pressure, the liquid metal can be readily controllable to connect/disconnect to the monopole antenna so that the physical length of the antenna reversibly tunes. The corresponding reversible resonant frequency changes from 4.9 GHz to 1.1 GHz. The antenna properties based on the liquid metal actuation were characterized by measuring the reflection coefficient and agreed well with simulation results. Additionally, the corresponding time-lapse images of controlling liquid metal in the channel were studied.

Non-Contact Probes for On-Wafer Characterization of Sub-Millimeter-Wave Devices and Integrated Circuits

Abstract: We present a novel non-contact metrology approach for on-wafer characterization of sub-millimeter-wave devices, components, and integrated circuits. Unlike existing contact probes that rely on small metallic tips that make physical contact with the device on the chip, the new non-contact probes are based on electromagnetic coupling of vector network analyzer (VNA) test ports into the coplanar waveguide environment of integrated devices and circuits. Efficient signal coupling is achieved via a quasi-optical link between the VNA ports and planar antennas that are monolithically integrated with the test device. Experimental validation of the non-contact device metrology system is presented for the first time to demonstrate the accuracy and repeatability of proposed approach for the 325-500-GHz (WR2.2) and 500-750-GHz (WR1.5) bands.

Crosstalk Corrections for Coplanar-Waveguide Scattering-Parameter Calibrations

Abstract: We study crosstalk and crosstalk corrections in coplanar-waveguide vector-network-analyzer calibrations We show that while crosstalk corrections can improve measurement accuracy, the effectiveness of the corrections depends on a number of factors, including the length of the access lines, transverse dimensions, the separation between the crosstalk standards, and the substrate configuration

High resolution aerosol jet printing of D-band printed transmission lines on flexible LCP substrate

Abstract: In this paper, aerosol jet printing technology is assessed for D-band RF applications for the first time. It describes the fabrication process, the technology assessment and the characterization of coplanar waveguides (CPW) lines and CPW to microstrip transitions on liquid crystal polymer (LCP) in the D band using silver nanoparticle aerosol jet printing process. Feature sizes with a resolution of 10 μm, which is the finest resolution among all of the digital printing technologies, were realized successfully. The conductivity of the sintered silver structures was half to that of bulk silver after sintering at temperatures up to 200 °C. Printed transmission lines demonstrated losses of 0.35 dB/mm at 110 GHz and 0.51 dB/mm at 170 GHz that are less than that of the insertion loss of the inkjet printing lines by an order of magnitude.

Packaging a $W$ -Band Integrated Module With an Optimized Flip-Chip Interconnect on an Organic Substrate

Abstract: This paper, for the first time, presents successful integration of a W-band antenna with an organically flip-chip packaged silicon-germanium (SiGe) low-noise amplifier (LNA). The successful integration requires an optimized flip-chip interconnect. The interconnect performance was optimized by modeling and characterizing the flip-chip transition on a low-loss liquid crystal polymer organic substrate. When the loss of coplanar waveguide (CPW) lines is included, an insertion loss of 0.6 dB per flip-chip-interconnect is measured. If the loss of CPW lines is de-embedded, 0.25 dB of insertion loss is observed. This kind of low-loss flip-chip interconnect is essential for good performance of W-band modules. The module, which we present in this paper, consists of an end-fire Yagi-Uda antenna integrated with an SiGe BiCMOS LNA. The module is 3 mm × 1.9 mm and consumes only 19.2 mW of dc power. We present passive and active E- and H-plane radiation pattern measurements at 87, 90, and 94 GHz. Passive and active antennas both showed a 10-dB bandwidth of 10 GHz. The peak gain of passive and active antennas was 5.2 dBi at 90 GHz and 21.2 dBi at 93 GHz, respectively. The measurements match well with the simulated results.

RF Performance of SOI CMOS Technology on Commercial 200-mm Enhanced Signal Integrity High Resistivity SOI Substrate

Abstract: RF performance of a 200-mm commercial-enhanced signal integrity high resistivity silicon-on-insulator (eSI HR-SOI) substrate is investigated and compared with its counterpart HR-SOI wafer. By measuring coplanar waveguide lines and substrate crosstalk structures, it is demonstrated that losses are completely suppressed leading to virtually lossless linear substrate. Moreover, a reduction of the second harmonic distortion by more than 25 dB is measured on eSI HR-SOI wafer compared with HR-SOI. Excellent matching between experimental dc and RF characteristics of fully depleted SOI MOSFETs measured on top of HR-SOI and eSI HR-SOI is demonstrated. Furthermore, digital substrate noise is reduced by more than 25 dB on eSI HR-SOI compared with HR-SOI, when injected noise varies from 500 kHz to 50 MHz. The eSI HR-SOI substrate is fully compatible with the CMOS process and could be considered as a promising solution for the RF front-end-modules integration and system-on-chip applications.

Dielectric properties of porous silicon for use as a substrate for the on-chip integration of millimeter-wave devices in the frequency range 140 to 210 GHz.

Abstract: In this work, the dielectric properties of porous Si for its use as a local substrate material for the integration on the Si wafer of millimeter-wave devices were investigated in the frequency range 140 to 210 GHz. Broadband electrical characterization of coplanar waveguide transmission lines (CPW TLines), formed on the porous Si layer, was used in this respect. It was shown that the dielectric parameters of porous Si (dielectric permittivity and loss tangent) in the above frequency range have values similar to those obtained at lower frequencies (1 to 40 GHz). More specifically, for the samples used, the obtained values were approximately 3.12 ± 0.05 and 0.023 ± 0.005, respectively. Finally, a comparison was made between the performance of the CPW TLines on a 150-μm-thick porous Si layer and on three other radiofrequency (RF) substrates, namely, on trap-rich high-resistivity Si (trap-rich HR Si), on a standard complementary metal-oxide-semiconductor (CMOS) Si wafer (p-type, resistivity 1 to 10 Ω.cm) and on quartz. 84.40.-x; 77.22.Ch; 81.05.Rm

A 600 GHz low-noise amplifier module

Abstract: A compact WR-1.5 (500-750 GHz) low-noise amplifier (LNA) circuit has been developed, based on a grounded coplanar waveguide (GCPW) technology utilizing 20 nm metamorphic high electron mobility transistors (mHEMTs). The realized six-stage LNA TMIC achieved a maximum gain of 15.4 dB at 576 GHz and more than 10 dB in the frequency range from 555 to 619 GHz. For low-loss packaging of the circuit, a waveguide-to-microstrip transition has been fabricated on a 20 ¼m thick GaAs substrate, demonstrating an insertion loss of only 1 dB between 500 and 720 GHz. The realized LNA module achieved a small-signal gain of 14.1 dB at 600 GHz and a room temperature (T = 293 K) noise figure of 15 dB at the frequency of operation.

Electromagnetic Behaviors of Thin Film CPW-Fed CSRR Loaded on UWB Transparent Antenna

Abstract: The electromagnetic behavior of the coplanar waveguide (CPW)-fed loaded complementary split-ring resonator (CSRR) to the ultrawideband (UWB) transparent antenna is presented in this letter. The transparent material known as conductive silver-coated thin films (AgHT-4) is one of the unique materials that is now being implemented in antenna designs. This material has very unique advantages of very thin thickness and high transparency. However, it exhibits different electromagnetic properties compared to the conventional Fire Retardant-4 (FR-4) due to its surface resistivity and conductivity. Meanwhile, split-ring resonators (CSRRs) are one of the metamaterial artificial structures that are implemented in antenna design for their unique negative permittivity/permeability properties. CSRR will be designed using the transparent material to achieve bandstop filter properties centered at 5.8 GHz so as to reduce the interferences from wireless local area network (WLAN) and dedicated short-range communication (DSRC) applications. The characteristics of the SRRs/CSRRs when implemented on the high resistivity thin film is compared to those implemented using copper radiating element.

A Fractal-Based Circularly Polarized UHF RFID Reader Antenna

Abstract: This letter presents the design of a coplanar waveguide (CPW) circularly polarized antenna for the central frequency 900 MHz, it comes in handy for radio frequency identification (RFID) short-range reading applications within the band of 902-928 MHz where the axial ratio of proposed antenna model is less than 3 dB. The proposed design has an axial-ratio bandwidth of 36 MHz (4%) and impedance bandwidth of 256 MHz (28.5%).

A Nesting-L Slot Antenna With Enhanced Circularly Polarized Bandwidth and Radiation

Abstract: In this letter, a new coplanar waveguide (CPW)-fed circularly polarized (CP) antenna with enhanced bandwidth and radiation is proposed for IEEE 802.16 Worldwide Interoperability for Microwave Access (WiMAX) and IEEE 802.11a wireless local area network (WLAN) applications. By protruding a symmetric T-type strip from CPW feedline, a broad input impedance bandwidth is obtained. To widen CP radiation bandwidth, a nesting-L slot (NLS) structure is introduced in the ground. The NLS is formed by an L-shaped perturbation implanted in the corner of an initial L-slot. The CP radiation bandwidth is enhanced by merging the first and second bands. The first band is generated by the initial L-slot, whereas the second band is obtained by the L-shaped perturbation. According to the measured results, the 10-dB return-loss bandwidth is about 110%, and the 3-dB axial-ratio bandwidth (ARBW) is about 60.9%. Finally, by placing a reflector underneath the antenna, one can obtain unidirectional radiation patterns with greatly improved gains.