Search

Key Clinical Message: Topical papaverine is an effective vasodilator that can be used for dilating small veins to accept venous couplers for thumb replantation. This technique corrects size mismatches for successful venous anastomosis and minimizes postoperative complications. Thumb replantation is a complex microsurgical procedure used to restore function and appearance after amputation. A successful venous anastomosis is essential in replantations; however, venous couplers can mismatch the size of veins and lead to obstacles. A 26‐year‐old male presented with a left thumb amputation caused by an electric saw injury. The amputated thumb was preserved and replantation surgery was performed 9 h post‐injury. The digital artery and veins were repaired but a size mismatch was found between the only salvageable superficial vein (0.7 mm) and the smallest available venous coupler (1 mm). The vein was dilated to accept the coupler by a series of applications of topical papaverine (1 mg/mL). This allowed venous anastomosis to be accomplished in 25 min. Postoperative follow‐up showed good thumb function, sensation, and circulation. Venous anastomosis is vital in thumb replantation to avoid venous congestion hence survival of the replanted thumb. Venous couplers shorten operative time and decrease the risk of postoperative complications. Papaverine is a vasodilator and facilitates venous anastomosis when veins and couplers are mismatched. This case demonstrates how papaverine, a vasodilator, may be used to improve surgical outcome during thumb replantation when small veins prevent venous coupler use. [ABSTRACT FROM AUTHOR]

This paper introduces a modified continuous mode class‐GF power amplifier (PA) incorporating a phase shift parameter to modify the drain voltage waveform. This modification significantly boosts the overlap area between the fundamental impedance and the second harmonic impedance, thereby providing increased flexibility in designing a broadband matching network. Additionally, a straightforward modified coupler network is proposed to effectively accommodate the expanded impedance design space. Experimental validation was conducted with a PA operating within the frequency range of 0.5–3.5 GHz. The results affirm the efficacy of the proposed approach, with the saturated output power ranging from 40.0 to 42.5 dBm, accompanied by a gain exceeding 10 dB. Furthermore, a remarkable drain efficiency ranging from 59% to 76.2% is achieved within the targeted frequency band. [ABSTRACT FROM AUTHOR]

Memory‐steel for smart steel structures – a review on recent developments and applications This study comprehensively examines recent advancements in the development and utilization of iron‐based shape memory alloy (Fe‐SMA), commonly known as memory‐steel, within the retrofitting of steel structures. The discussion is structured into several key areas. Initially, a thorough analysis of the material properties of Fe‐SMA is presented, focusing on aspects such as shape memory effect and super‐elasticity. Subsequently, the application of Fe‐SMA in prestressed strengthening of steel structures is elucidated, encompassing its role in reinforcing steel girders, connections, and addressing fatigue crack repairs. Various strengthening methodologies are explored, including the utilization of mechanically anchored or adhesively‐bonded Fe‐SMA. The study delves into an in‐depth examination of the behavior exhibited by Fe‐SMA‐to‐steel bonded joints. Notably, the research highlights the practical application of Fe‐SMA in strengthening a 113‐year‐old steel bridge. Furthermore, innovative applications of Fe‐SMA as pipe couplers are introduced, showcasing its versatility in diverse structural contexts. [ABSTRACT FROM AUTHOR]

This study reviews the recent works on the development and application of iron‐based shape memory alloy (Fe‐SMA), the so‐called memory‐steel, for steel structures. First, the studies on the material properties of Fe‐SMA in terms of shape memory effect and superelasticity are discussed. Next, the use of Fe‐SMA in prestressed strengthening of steel structures is explained, including the applications in strengthening of steel girders, connections, and fatigue crack repairs. Various strengthening solutions such as using mechanically anchored or adhesively‐bonded Fe‐SMA, as well as the studies on the behavior of the Fe‐SMA‐to‐steel bonded joints, are discussed. The use and application of Fe‐SMA for strengthening of a 113‐years steel bridge has been explained. In addition, studies on the innovative application of the Fe‐SMA as pipe couplers are presented. At the end, innovative ongoing research on the additive manufacturing of architected Fe‐SMA (4D‐printing) are discussed. [ABSTRACT FROM AUTHOR]

In this letter, novel spiral‐coupled transmission lines are used to obtain a high‐performance microstrip coupler. The advantages of the proposed microstrip coupler are novel structure, filtering frequency response, suppressed harmonics up to second harmonics, transmission poles, low losses, compact size, and good phase balance. The proposed structure is novel and different from the previous coupler designs such as rate‐races, rings, and branch‐lines types. It is presented for the first time in this work with a very small size and good performance. The size of this coupler is only 82.6 mm2 (0.004 λg2). The common port return loss is 33 dB and the insertion losses at port 2 and port 3 are 2.2 and 2.7 dB, respectively. To prove the accuracy of the design method and simulation results, the proposed coupler is fabricated and measured where the measurement results confirm the simulation results and the proposed design method. [ABSTRACT FROM AUTHOR]

This letter presents a mixed strategy to design broadband high‐efficiency power amplifiers (PAs), where the mixed continuous mode PA provide theoretical impedances. Furthermore, only a single one‐stage coupler circuit with appropriate terminals is exploited to satisfy the fundamental and second harmonic impedances requirements necessary for mixed continuous mode PA realization. Combination of mixed modes PAs' desired impedances and the coupler's impedance frequency modulation trajectory, the available design frequency band can be determined. For validation, a broadband high‐efficiency PA covering the frequency range 0.4–3.0 GHz is designed and then fabricated using a CGH40010F transistor. Measured results indicate that the implemented PA can deliver saturated output power of 40.2–42.7 dBm across the frequency range 0.4–3.0 GHz, with drain efficiency of between 60.4% and 74.5%. [ABSTRACT FROM AUTHOR]

Multi‐section broadband couplers with arbitrary phase differences and arbitrary power‐dividing ratios are presented. By using the even‐ and odd‐mode analysis, the closed‐form design equations are derived and then used to determine the circuit parameters of the proposed couplers. Furtherly, the corresponding performance analysis in terms of the bandwidth requirement is provided. Finally, the design procedure of the proposed general couplers is presented. For verification, several couplers with different phase differences and power‐dividing ratios are designed, fabricated and measured. The measured results agree well with the simulated results. [ABSTRACT FROM AUTHOR]

In this paper, a millimeter‐wave Butler matrix with flexible phase differences is proposed using the substrate integrated suspended line technology. To begin with, a low‐loss substrate integrated suspended line (SISL) circular patch coupler consisting of four circular sectors is presented, achieving arbitrary phase difference and coupling coefficient by adjusting the angle and radii of the sectors. Based on the proposed coupler, two prototypes of the SISL Butler matrix are designed, fabricated and measured for the demonstration. In prototype I, the crossovers are removed and a flexible phase difference is obtained with an area size of 2.5 λg × 2.8 λg. In prototype II, both the crossovers and 45° phase shifters are removed and the phase differences of ±45° and ±135° are obtained with an area size of 1.86 λg × 2.24 λg. Low crosstalk between components and minimal radiation loss can be achieved by the SISL self‐packaged characteristic and electromagnetic shielding. For both prototypes, the measured insertion losses are less than 2 dB at 26 GHz, including the loss of transitions and connectors, and the measured phase errors are less than ±10° within a bandwidth of more than 10%. The proposed Butler matrix shows the advantages of compact size, low loss and high integration. [ABSTRACT FROM AUTHOR]

We demonstrate the first multicore multimode fiber (MC‐MMF) for passive optical network, efficiently utilizing the space division multiplexing to reduce the upstream traffic losses by eliminating the need of multiple feeder fibers. From the simulation results, the error‐free performance is achieved for upstream transmission over 18 modes of MC‐MMF. The differential group delay per unit length of fiber is also analyzed at different modes of MC‐MMF with attenuation per unit length of fiber, respectively. [ABSTRACT FROM AUTHOR]

A novel balanced power amplifier (BPA) using compact coupler with rhombus resonators is presented. In this design, a new method is presented to analyze the proposed rhombus‐shaped resonator based on the LC equivalent circuit. A new class F power amplifier is designed to improve performances of the BPA. The results show that the performance of the proposed BPA is improved by using the proposed harmonic suppressed coupler at the design structure. The designed BPA operates at 1.25 GHz and delivers 29 dB output power with a gain of 17.9 dB and drain efficiency (DE) of 65.2%. The presented BPA is realized using ATF‐34143 transistors in GaAs pHEMT technology and fabricated on the RT/Duroid 5880 substrate with a thickness of 31 mil. [ABSTRACT FROM AUTHOR]

This study designs and analyzes Complex Ratio Measuring Unit (CRMU) and a Six‐port Reflectometer (SPR) at a center frequency of 2.4 GHz. CRMU is designed using a compact size and wideband 3 dB‐branch line coupler (BLC) and 3 dB‐Wilkinson power divider with enhanced series‐diamond stubs. The usage of these compact components leads to a compact size and improves the operating bandwidth. The idea of designing SPR is based on integrating a CRMU with 2 directional couplers along with isolator rather than a single BLC; to get a signal balance that enhances the quality of the reflection coefficient measurement. From the measurement result, it is found that the bandwidth of the CRMU and SPR is 1.7 GHz and the dimension of the CRMU is 60 × 45 mm. The proposed CRMU is fabricated using RT/duroid 5880 substrate with thickness of 0.38 mm. The dimension of the CRMU is 13 × 6.5 mm. The simulation and measurement results for both CRMU and SPR show good agreement. [ABSTRACT FROM AUTHOR]

A multi-layer 3-dB substrate integrated waveguide coupler is presented in this article. As a promising technique, the multi-layer substrate integrated waveguide has been widely used in microwave and millimeter circuits and systems for its decrease in size. This design combines the Bethe hole coupling theory with the SIW technology to reduce the height and integrate with other planar circuits. More importantly, the strong coupling (3-dB) coupler presented in this article utilizes the higher frequency band of TE10 mode to get a relatively bigger radius of aperture and in turn reduce the number of coupling sections, which significantly decrease the size of the coupler. The simulated results are in good agreement with the measured data. [ABSTRACT FROM AUTHOR]

The stimulating connection between the counter-intuitive optical pulling effects and the Lorentz force has not been investigated in literature. This work demonstrates that multiple absorbing or non-absorbing dielectric Rayleigh objects can be pulled locally with gradientless travelling waves outside a finite-sized cylindrical nano or micro waveguide, if it is made up of a hollow core along with the cladding of at least two different dielectrics of appropriate refractive indices. Lorentz force analysis reveals that the bound surface charges of Rayleigh scatterer experience backward force, which overcomes the positive bulk force and ultimately results in the net pulling of the scatterer for several spatial regions outside the waveguide. Finally, in order to control the pulling of multiple Rayleigh particles based on scattering force and binding force, we have proposed a possible cylindrical coupler set-up. This work may open a new window of optical pulling force due to the exclusion of conventional structured tractor beams along with the artificial exotic matters. [ABSTRACT FROM AUTHOR]

ABSTRACT This article presents a novel reflective phase shifter based on wideband multi-section 3-dB hybrid coupler in slot-coupled structure. By terminating coupled and transmission ports of coupler with rectangular microstrip loads, reflective phase shifter is achieved. It designed on multilayer Rogers RO4003C substrate. The configuration consists of elliptically shaped transmission line and the combination of rectangular and elliptical shaped slots on the ground plane. To improve characteristics of the designed coupler especially in lower frequency band, multi-section transmission line and altering shape of the slot on ground is proposed. By etching extra rectangular slots on the ground plane the overall size reduction is achieved. Measurement results of the proposed coupler demonstrate coupling of 3 ± 0.7 dB with 90° ± 0.6 phase shift over 1-6 GHz (143%). The novel reflective phase shifter based on the designed coupler provides phase deviation less than 0.7° on 1.2-4.8 GHz (120%). The obtained return loss is better than 10 dB as well as insertion loss is less than 1.2 dB at the frequency band of interest. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:567-573, 2017 [ABSTRACT FROM AUTHOR]

ABSTRACT A tunable multiwavelength erbium-doped ring cavity fiber laser based on a Fabry-Perot filter and Mach-Zenhder interferometer is proposed. A tunable single wavelength laser is realized from 1526.8 to 1558.6 nm, and the space interval and peak power shift are less than 2.6 nm and 0.8 dBm, respectively. A dual- and tunable triple-wavelength laser are achieved, and the power fluctuation of the dual- and triple-wavelength lasers is less than 0.153 and 1.28 dBm, respectively, at room temperature within a 20-min scan time. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:1790-1794, 2016 [ABSTRACT FROM AUTHOR]

Abstract: The authors present in this article an overview of the six port reflectometer (SPR). They realized SPR using broadside coupled lines for achieving ultrawide band, which is essential for its working as an alternative network analyzer. [ABSTRACT FROM AUTHOR]

In this article, the design approach, the implementation, and experimental results of multiband branch-line couplers operating at arbitrary frequencies are presented. The conventional branch-line coupler structure is adapted to multiband operation by shunting its four ports with multiband reactive networks. The performance of the proposed multiband couplers is theoretically analyzed and optimized through the even-odd mode circuit analysis. Dual-band (2.4-3.5 GHz), triple-band (1.5-2.4-4.2 GHz), and quad-band (1.5-2.4-3.5 GHz) microstrip branch-line couplers have been realized and tested to verify the design method. The good experimental results (input return loss greater than 15 dB and amplitude imbalance lower than 0.7 dB) show excellent agreement with theoretical and simulated ones, thus validating the proposed approach. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:117-129, 2014. [ABSTRACT FROM AUTHOR]

This article presents an overview of the generalized negative-refractive-index transmission-line (G-NRI-TL) and summarizes the design equations that determine the frequencies of each of its four passbands. Specific multiband devices to which G-NRI-TLs have been applied are discussed: both a dual-band coupled-line coupler operating at 2.7 and 4.7 GHz and a printed single-ended all-pass cell with two pairs of right- and left-handed bands are explained. The details of how each may be fabricated in a fully-printed layout are provided and simulated and measured results are given. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE 22:459-468, 2012. [ABSTRACT FROM AUTHOR]

This mini review gives an overview of the synthesis of polyurethanes and polyesters with pendant hydroxyl groups performed mainly in our group. Significant for the synthesis of most of these polymers with hydroxyl-functional side groups is that no protection groups are needed. This is realised either by generating the OH group during polymer synthesis-demonstrated by the preparation of hydroxyl-functional polyurethanes from dicarbonate monomers and diamines-or by using catalysts which discriminate between primary and secondary OH groups-demonstrated by the synthesis of hydroxyl-functional polyesters based on malic acid using scandium triflate as catalyst. In addition, the potential of carbonate couplers for the synthesis of multifunctional polyurethane is presented. The application of such multifunctional polyurethanes as antimicrobial polymers and coatings is briefly discussed. Copyright © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

New passive millimeter wave circuits built on thin alumina substrate are presented. A six-port model is generated using measurement results of a 90° hybrid coupler. Good correlations between model and circuit measurements are proven. The proposed model is suitable for advanced system simulations of V-band wireless personal area networks. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 2104–2108, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25377 [ABSTRACT FROM AUTHOR]

An experimental investigation about the Circular In-Phase Hybrid Ring power divider is presented. This device is a Five Ports Hybrid Ring that has potential applications in Antenna Array feeding Networks. Its principal behavior characteristics are analyzed and compared with a conventional device. A prototype, which includes the effects of SMA connectors, was designed and measured corroborating the behavior of this circuit as a conventional five ports microstrip hybrid. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2314–2317, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22714 [ABSTRACT FROM AUTHOR]

The article discusses the European Union's Program for Integrated Earth System Modelling (PRISM) infrastructure project aims at designing a flexible and friendly user environment to assemble, run and post-process Earth System models. The project was started in December 2001 with a duration of three years. PRISM is emerging as a core strategic software infrastructure for building the European research area in Earth system sciences.

This paper presents an optically controlled broadband phase-shifter using a parallel-line coupler, that takes advantage of high-resistivity silicon photo-absorption at 840 nm. A continuously variable phase-shifting of 120° is achieved at 11 GHz with Δ|S21| < 5 dB and with |S11| < -15 dB in a large frequency band (6–15 GHz). © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 570–573, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21232 [ABSTRACT FROM AUTHOR]

A new configuration of a three-port rectangular microstrip power divider and coupler has been proposed. It can easily implement unequal power division of a large ratio, i.e., the power coupled to the third port can vary from -3 to -26 dB. The configuration has been analyzed using a transmission-line model, as well as method-of-moments-based software. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 219–223, 2001. [ABSTRACT FROM AUTHOR]

A homodyne multiport network analyzer is proposed for the characterization of N-port microwave devices, circuits, and systems. The single six-port junction used as a wave correlator is operated as a two-channel wave receiver. The use of an additional test set, which comprises two switching matrices and N bidirectional couplers, allows the measurements of complete S-parameter matrices of N-port devices. By comparison to existing network analyzers, the proposed system is homodyne in the sense that it does not require any frequency down-conversion to determine the phase information, and uses only one single six-port junction to obtain complex S-parameter measurements from only scalar measurements. A detailed description of the proposed system is presented. Two- and three-port structures are measured, and the results are compared to the data obtained by a two-port commercial network analyzer. © 2000 John Wiley & Sons, Inc. Microwave Opt Technol Lett 24: 63–67, 2000. [ABSTRACT FROM AUTHOR]

ABSTRACT This letter reports a novel single-layer planar coupled-line coupler with multiple prominent advantages. These advantages include compact size, wideband filter-integrated coupling and transmission, unequal power division, flat phase difference, and inherent DC-block function between two arbitrary ports. Eventually, a microstrip prototype with 7.1-dB power-division ratio is implemented for verification, whose fractional bandwidth of 20-dB return loss is 58.4%. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:121-123, 2016 [ABSTRACT FROM AUTHOR]

In this paper, we demonstrate an X-band balanced power amplifier using a novel microstrip line dc blocking impedance-transforming branch-line coupler (DCITBC). This novel coupler has the function of dc blocking, which can easily cascade two stages of an active circuit together. Therefore, we can reduce the cost and the circuit size. The measured power-added efficiency of this balanced power amplifier is 50% over the 9.8–10.2 GHz band, with an associated gain of 9 dB and 25 dBm output power. Additional important results are the superior performance of the harmonic suppression; the measured result shows a second harmonic below -40 dBc without an extra harmonic rejector. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 20: 192–195, 1999. [ABSTRACT FROM AUTHOR]

Using the spectral domain method, theoretical analysis of the characteristics of coupled suspended microstrip lines with floating conductor is presented in detail. The distributions of electrical charges on the coupled microstrip lines and floating conductor are studied, and a set of basis functions used in the calculation is obtained. Detailed numerical results and design curves are presented, and an experimental wideband 2.5-dB coupler is designed and measured. The test results are in agreement with theoretical values. This type of coupler is simple in construction and capable of realizing tight coupling (3 dB or higher) in microwave integrated circuits (MIC) with high directivity. [ABSTRACT FROM AUTHOR]

The article presents information on a study that examined interdependence, individual differences and problem-solving variables as linked to relationship satisfaction and relationship commitment for both black and white dating heterosexual couples. Data were collected from both partners of 61 white dating couples and 34 black dating couples. None of the couples cohabited. Relationship satisfaction was assessed by the three-item Kansas Marital Satisfaction Scale. The first analysis addressed racial differences in men's and women's personal background scores, men's and women's relationship satisfaction and relationship commitment, and the relationship background scores. The final analysis tested whether the interdependence, individual differences, and problem-solving correlates of both relationship satisfaction and relationship commitment differed between men and women. Consistent with findings based on primarily white heterosexual and gay/lesbian couples, variables from the interdependence, individual differences, and problem-solving models accounted for significant portions of variability in both relationship satisfaction and relationship commitment for both black and white respondents and for both male and female respondents. Taken together, this pattern of findings supports the conclusion that variables from the interdependence, individual differences, and problem-solving models are robust predictors of relationship functioning.

A metal mesh coupler, which makes use of the evanescent-wave coupling between a metal mesh and a dielectric plate, has been developed as a quasi-optical component for millimeter and submillimeter wavelengths. The transmission properties of this type of coupler are investigated experimentally and theoretically at the millimeter-wave frequencies. The transmittance of the evanescent-wave coupler with a capacitive metal mesh can be adjusted by more than 70 percent by altering the spacing between the capacitive mesh and the silicon plate by less than λ/140 at 56 GHz. The experimental and theoretical results show that large and rapid variations of transmittance in the coupler arise from changes in the effective refractive index of the silicon plate due to the evanescent-wave coupling effect. An equivalent circuit for the evanescent-wave couplers is developed for use in the design of coupler configuration. © 1998 Scripta Technica. Electron Comm Jpn Pt 2, 80(10): 49–57, 1997 [ABSTRACT FROM AUTHOR]

In this article, we present the design and the measurement of two hybrid couplers for millimeter-wave applications realized in the BiCMOS9MW 130nm process (ST Microelectronics). The aim is to demonstrate several miniaturization possibilities of a conventional branchline coupler while maintaining a constant 90° phase shift and a low insertion loss over the full 57-66-GHz band. The first miniaturized coupler is composed of meandered transmission lines; the second is a quasi-lumped quadrature coupler with discrete capacitors. The performance of these circuits is compared with the most recent on-chip 60-GHz couplers. We especially demonstrate the possibility to achieve state-of-the-art performance while using miniaturization techniques. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:2221-2223, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27079 [ABSTRACT FROM AUTHOR]

A compensation technique to generate enhanced return loss and directivity is proposed by using additional branch lines for a broadside coupler. The branch lines at all ports are added to reduce the port impedance, resulting in improvement of impedance matching for the tight coupled broadside coupler. The measured results of the proposed low-temperature cofired ceramic (LTCC) coupler show more than 4 dB enhancements of return loss and isolation, compared with those of the conventional one. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3134–3136, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23930 [ABSTRACT FROM AUTHOR]

This article describes a symmetric capacitor-compensated microstrip directional-coupler design with very high directivity. The compensation capacitors are incorporated between the coupling lines as interdigital type on the PCB board. The prototype directional-coupler shows 19.6 dB coupling factor and achieves very high directivity of more than 45 dB at 1.9 GHz. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2801–2803, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23800 [ABSTRACT FROM AUTHOR]

Two kinds of groove structure for shortening and broadening the coupling lengths of Ti:diffused LiNbO3 directional couplers are presented. The coupling lengths as functions of the depth, width, and spacing of the grooves were numerically calculated. The results show that the maximum shortening of the coupling length is up to 43%, and the maximum broadening is even larger, depending on the groove depth. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 301–303, 2001. [ABSTRACT FROM AUTHOR]

A case study is presented for a 43-year-old woman with severe oedematous, eczematous dermatitis on her scalp and face. It mentions that patch test was conducted for the evaluation of dermatitis. It concludes the use of a hair dye ingredients to detect less common allergens and allergic contact dermatitis caused by 1-naphthol.

Empty substrate integrated waveguide (ESIW) is an improvement of the well‐known substrate integrated waveguide. While maintaining the low cost, easy manufacturing, small size, and integration with other circuits in the same substrate, ESIW decreases the related losses by removing the dielectric substrate, thus rendering it more interesting for practical applications. A wide band transition has been already developed to connect ESIW to microstrip lines. Filters, couplers, and antennas have also been developed in ESIW. For multilevel configurations, where different ESIW devices are implemented in different stacked substrates, a transition is needed that connects ESIW lines in different substrate levels. A low reflection wideband transition is presented for connecting two stacked ESIW lines. [ABSTRACT FROM AUTHOR]