Broadband Transition Research Articles

Broadband Transition between Rectangular Waveguide and Substrate Integrated Waveguide Based on Double Rhombus Antenna Probe

The paper presents a design of rectangular waveguide-SIW transition, which provides a broadband and low insertion loss performance. The broadband transition is realized by using double-rhombus antenna probe inserted into rectangular metal waveguide. The transition is simulated and measured at 9-20GHz. The measured results show that a good agreement with simulation and an insertion loss less than 2.8 dB and a return loss better than 10 dB are obtained at 10–18.5 GHz for a back-to-back structure.

Broadband right‐angle transition from substrate‐integrated waveguide to rectangular waveguide

A broadband right-angle transition from a substrate-integrated waveguide (SIW) to a rectangular waveguide (RWG) is proposed. A coupling aperture etched on the broad wall of the SIW and two stepped ridges embedded in the RWG flange are designed for good matching between both waveguides. A Ka-band prototype is designed and fabricated. Good agreement between the measured and simulated results is obtained. The measured results show an insertion loss <;0.55 dB and a return loss below -15 dB from 31.3 to 38.35 GHz. This broadband transition may be used in microwave and millimetre-wave circuits and systems.

Broadband transition between microstrip line and conformal surface plasmon waveguide

We propose a broadband and high-efficiency transition from a microstrip line to a conformal surface plasmon (CSP) waveguide that is made of an ultrathin corrugated metallic strip, to transform the guide wave into a spoof surface plasmon polariton (SPP) in the microwave region. The transition consists of three parts: a convertor which converts the direction of the electric field from perpendicular to parallel to the strip, a matching area with gradient corrugations and a flaring metallic line to match both the momentum and impedance, and a CSP waveguide to support the SPP waves. A back-to-back transition sample is fabricated using the proposed method. Experimental results of S parameters and near-field distributions verify the excellent performance of the sample to transform guided waves to SPPs and transmit SPP waves in a wide band. The sample exhibits low energy loss when the CSP waveguide is bent or even twisted. The proposed transition may have potential applications in integrating conventional microwave devices with the SPP devices.

Broadband transition between substrate integrated waveguide and rectangular waveguide based on ridged steps

Broadband transition between substrate integrated waveguide and rectangular waveguide based on ridged steps

BROADBAND RECTANGULAR WAVEGUIDE TO GCPW TRANSITION

A broadband transition design between rectangular waveguide and GCPW is proposed and studied. The E-fleld of GCPW is designed to be gradually changed to that of waveguide via the simple tapered probes and metallic vias. The planar circuit of the transition is fabricated by low cost standard PCB process. The tolerance analysis for this transition is also given. A back-to-back transition prototype at Ka-band is fabricated and measured. The measurement results show that maximum insertion loss of 0.75dB and return loss of better than 15dB are obtained within a desired frequency range from 26.5 to 40GHz. The measurement results agree well with simulation results, which validate the feasibility of this design.

A W-Band Low-Loss and Wideband LTCC Transition From Waveguide to Microstrip

A broadband transition structure from rectangular waveguide (RWG) to microstrip line (MSL) is presented for the realization of the low-loss packaging module using Low-temperature co-fired ceramic (LTCC) technology at W-band. In this transition, a cavity structure is buried in LTCC layers, which provides the wide bandwidth, and a laminated waveguide (LWG) transition is designed, which provides the low-loss performance, as it reduces the radiation loss of conventional direct transition between RWG and MSL. The design procedure is also given. The measured results show that the insertion loss of better than 0.7 dB from 86 to 97 GHz can be achieved.

BROADBAND SUBSTRATE INTEGRATED COAXIAL LINE TO CBCPW TRANSITION FOR RAT-RACE COUPLERS AND DUAL-BAND COUPLERS DESIGN

In this paper, broadband transitions from substrate integrated coaxial line (SICL) to a conductor-backed coplanar waveguide (CBCPW) are proposed and designed. Measurement results show that the insertion loss and return loss are better than i0:5dB and i10dB, respectively from 0 to 13GHz. Then, for verifying the performance of SICL and the validity of SICL transition design, a 3dB SICL rat-race coupler operating at 2.3GHz is designed, fabricated, and measured. Compared with the conventional microstrip line coupler, this SICL coupler maintains good performance but with a remarkable 24% reduction in size. At last, a 10dB dual-band coupled SICL coupler operating at 2.4/5.8GHz is proposed, and the measured results agree well with the schematic and electromagnetic simulated results. The measured results demonstrate that the fabricated bandwidths are 30% and 12.8%, the jS31j are i10:1dB and i10:3dB, the directivities are 18dB and 20dB at the low (2.4GHz) and high (5.8GHz) operating frequencies, respectively. Compare with the dual-band coupled microstrip line coupler, performance of the dual-band coupled SICL coupler is enhanced.

Broadband transitions for membrane-based coplanar waveguides on highly-conductive silicon substrates

Abstract. We present a transition from a contact structure built on highly-conductive silicon to a coplanar waveguide (CPW) fabricated in membrane technology. Test structures were fabricated and measured. The silicon-to-membrane transition is suitable for on-wafer probing and provides less than −10 dB measured reflection in the frequency range from 1 to 110 GHz. Measured and calculated values of the propagation constant of the membrane CPW agree well in the entire frequency range.

ATMOSPHERIC RETRIEVAL FOR SUPER-EARTHS: UNIQUELY CONSTRAINING THE ATMOSPHERIC COMPOSITION WITH TRANSMISSION SPECTROSCOPY

We present a retrieval method based on Bayesian analysis to infer the atmospheric compositions and surface or cloud-top pressures from transmission spectra of exoplanets with general compositions. In this study, we identify what can unambiguously be determined about the atmospheres of exoplanets from their transmission spectra by applying the retrieval method to synthetic observations of the super-Earth GJ 1214b. Our approach to infer constraints on atmospheric parameters is to compute their joint and marginal posterior probability distributions using the MCMC technique in a parallel tempering scheme. A new atmospheric parameterization is introduced that is applicable to general atmospheres in which the main constituent is not known a priori and clouds may be present. Our main finding is that a unique constraint of the mixing ratios of the absorbers and up to two spectrally inactive gases (such as N2 and primordial H2+He) is possible if the observations are sufficient to quantify both (1) the broadband transit depths in at least one absorption feature for each absorber and (2) the slope and strength of the molecular Rayleigh scattering signature. The surface or cloud-top pressure can be quantified if a surface or cloud deck is present. The mean molecular mass can be constrained from the Rayleigh slope or the shapes of absorption features, thus enabling to distinguish between cloudy hydrogen-rich atmospheres and high mean molecular mass atmospheres. We conclude, however, that without the signature of Rayleigh scattering--even with robustly detected infrared absorption features--there is no reliable way to tell if the absorber is the main constituent of the atmosphere or just a minor species with a mixing ratio of <0.1%. The retrieval method leads us to a conceptual picture of which details in transmission spectra are essential for unique characterizations of well-mixed atmospheres.

The unsustainable directionality of innovation – The example of the broadband transition

Information and communication technology (ICT) can be seen as a general-purpose technology with wide-ranging socio-economic and environmental implications across sectors. ICTs also constitute a system of technologies with stronger internal links since the emergence of the Internet and broadband as a new information infrastructure. The new infrastructure has co-evolved with widespread integration of ICTs in everyday life, and consumer demand has been decisive for ICT innovation. This article explores the environmental directionality of ICT innovation and the broadband transition, focusing mainly on energy impacts. It is argued that much innovation tends to develop in an unsustainable direction and that public regulation falls far short of the challenge. Transition theory is applied to analyze the background for the unsustainable development and the reasons why environmental concerns do not figure more prominently in the broadband transition. Finally, it is discussed how the direction of ICT innovation could be influenced in order to realize more of the positive sustainability potential.

A Broadband U-Slot Coupled Microstrip-to-Waveguide Transition

A novel planar broadband microstrip-to-waveguide transition is proposed in this paper. The referred waveguide can be either rectangular waveguide or ridged waveguide. The transition consists of an open-circuited microstrip quarter-wavelength resonator and a resonant U-shaped slot on the upper broadside wall of a short-circuited waveguide. A physics-based equivalent-circuit model is also developed for interpreting the working mechanism and providing a coarse model for engineering design. The broadband transition can be regarded as a stacked two-pole resonator filter. Each coupling circuit can be approximately designed separately using the group-delay information at the center frequency. In addition to its broadband attribute, the transition is compact in size, vialess, and is highly compatible with planar circuits. These good features make the new transition very attractive for the system architecture where waveguide devices need to be surface mounted on a multilayered planer circuit. Two design examples are given to demonstrate the usefulness of the transition: one is a broadband ridged-waveguide bandpass filter and the other is a surface-mountable broadband low-temperature co-fired ceramic laminated waveguide cavity filter. Both filters are with the proposed transition for interfacing with microstrip lines, showing promising potentials in practical applications.

Raman laser cooling of solids

A new approach is proposed for 3-D laser cooling of solids. Stimulated Raman scattering on a narrowband electronic transition is used in conjunction with 1-photon optical pumping on a broadband transition to provide a mechanism that cools all the vibrational modes of solids while conserving energy and momentum, photon by photon. The individual steps in the 2-photon Raman process are 4f–5d and 5d–4f transitions which are electric-dipole-allowed (broadband) transitions that form a Λ-system. By contrast, the 2-photon transition between the 4f states of the rare earth ion is narrowband. By considering examples of Ce3+ ions in Y3Al5O12 and CeF3, elevated transition rates are predicted to offer substantial improvement over anti-Stokes fluorescence cooling when all 1-photon detunings exceed their corresponding Stokes shifts.

Broadband transition between waveguide and substrate integrated waveguide based on quasi-Yagi antenna

A novel broadband waveguide-to-substrate integrated waveguide transition is presented. The broadband transition is realised by using an antipodal quasi-Yagi antenna probe inserted into a rectangular metal waveguide. The transition is simulated and measured at 8–18GHz. The measured results show that good agreement with simulation and an insertion loss less than 2.7dB and a return loss better than 10dB are obtained at 9.5–17.5 GHz for a back-to-back structure.

A Broadband Transition Design for a Conductor-Backed Coplanar Waveguide and a Broadside Coupled Stripline

A broadband transition design between broadside coupled stripline (BCS) and conductor-backed coplanar waveguide (CBCPW) is proposed and studied. The E-field of CBCPW is designed to be gradually changed to that of BCS via a simple linear tapered structure. Two back-to-back transitions are simulated, fabricated and measured. It is reported that maximum insertion loss of 2.3 dB, return loss of higher than 10 dB and group delay flatness of about 0.14 ns are obtained from 50 MHz to 20 GHz.

Broadband Transition between Substrate Integrated Waveguide (SIW) and Rectangular Waveguide for Millimeter-Wave Applications

In this paper, a broadband and simple vertical transition between substrate integrated waveguide and standard air-filled rectangular waveguide is design and experimentally verified. From full-wave simulation of the structure, a relative bandwidth of 19.5% in W-band with return loss better than 20dB is reached. Then, five copies of back-to-back connected transitions are fabricated on RT/Duroid 5880 substrate. The experimental results show that the transition pairs have an average of 15% relative bandwidth with return loss better than 12dB and insert loss lower than 1.2dB. To explain the differences between simulated and tested results, an error analysis is presented.

Design of broadband transitions for substrate integrated circuits

AbstractWe present a methodology to enhance bandwidth of the conductor backed coplanar waveguide‐to‐substrate integrated waveguide and microstrip‐to‐integrated waveguide transitions.Our approach exploits metalized vias partially protruding into substrate in the transition region as tuning elements. This allows us—for the considered type of transition—to increase useable bandwidth. Geometry parameters, including positions and sizes of extra vias, are adjusted using simulation‐driven optimization procedure that exploits coarsely‐discretized electromagnetic (EM) models of the transitions and the adaptively adjusted design specifications technique. The optimal design is obtained at a low‐computational cost corresponding to a few high‐fidelity EM simulations of the structure of interest (typically comparable with the number of design variables). Our technique is demonstrated with the X‐band designs. © 2011 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:2942–2945, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26391

Mode Coupling Between Substrate Integrated Waveguide and Coplanar Waveguide for Traveling-Wave Electrooptical Modulator

A traveling-wave electrooptical modulator that makes use of a mode coupling mechanism between a substrate integrated waveguide (SIW) and coplanar waveguide (CPW) is proposed for millimeter-wave (mmW) radio-over-fiber applications. In this structure, SIWs are added at the input/output ports of conventional modulators from which mode conversion and signal transfer take place between lossy CPW traveling-wave electrodes and low-loss mmW SIW terminals. Such a gradual coupling from SIW to CPW in the modulation path creates a nonuniform field overlap integral and gives the ability of using the modulator at higher frequency. A laser micromachining technique for a transparent LiNbO3 substrate and a titanium in-diffusion technique for achieving a good optical field confinement are used to fabricate the SIW and optical waveguide, respectively. The bending structure of the SIW, fabrication of pad resistors, and broadband transitions are considered in the proposed modulator. 7-GHz bandwidth was measured for the proposed modulator at 60 GHz.

Synthesis of Ba2Si3O8 : Eu2 + Phosphor for Fabrication of White Light-Emitting Diodes Assisted by ZnCdSe/ZnSe Quantum Dot

Bluish green-emitting -doped barium silicate phosphor was synthesized via a conventional solid-state reaction chemistry, and Eu concentration and firing temperature were optimized toward its highest luminescent efficiency. phosphor could be excited under near-UV wavelengths and exhibited a broad emission band ( transition of ) due to the strong coupling of Eu activator with the surrounding host. Phosphor-converted (pc) light-emitting diode (LED) was fabricated by combining phosphor with a near-UV LED. To fabricate white LED with a high color rendering index, a highly efficient orange-emitting ZnCdSe/ZnSe core/shell quantum dot was incorporated with an unconventional layered design into the above phosphor-based pc-LED and their electroluminescent properties are described.

Broadband transition between rectangular waveguide and substrate integrated waveguide

A novel broadband waveguide-to-substrate integrated waveguide transition is presented. The transition is realised by using a fin line probe inserted into a rectangular metal waveguide. A single back-to-back transition covering the KA band is designed, fabricated and tested. Measured results show that good agreement with simulation, an insertion loss less than 1.4 dB and a return loss better than 15 dB at 25–40 GHz are obtained for a back-to-back structure. This broadband transition between the rectangular waveguide and substrate integrated waveguide can be used widely in microwave and millimetre-wave circuits and systems.

Millimetre-wave broadband transition of substrate-integrated waveguide to rectangular waveguide

Proposed is a new substrate-integrated waveguide to air-filled rectangular waveguide (WR-10) transition for use at millimetre-wave frequencies. The transition combines the features of low return loss and low insertion loss over the 42 GHz bandwidth and it can be manufactured without a high degree of complexity. A 75–115 GHz band prototype of the proposed broadband transition is designed and fabricated. Simulated and measured results of the prototyped back-to-back transition show good agreement.