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This paper presents a novel structure for ultra broadband 4∶1 broadside-coupled PCB impedance transformer. Analysis, simulations and measurements of the developed transformer are introduced and discussed. Three prototypes of the proposed structure are implemented at center frequencies 5.65 GHz, 4.35 GHz and 3.65 GHz, respectively with fractional bandwidth of greater than 180 %. The implemented transformers...
In this paper broadband branch-line couplers with loose couplings (less than −10 dB) utilizing open/short-circuited coupled-transmission lines are proposed. By applying the equivalent admittance approach to the proposed branch-line coupler, broadband characteristics with a relative bandwidth of 47.5% for 20 dB return loss and directivity can be obtained in the case of the branch-line coupler with...
In this paper a microwave permittivity sensing system based on a super-heterodyne reflectometer is presented. A set of two high directivity directional couplers is utilized for the derivation of a reference and a reflection measurement channel from a 14 –18 GHz stimulus. Integrated Gilbert-cell circuits were fabricated in a SiGe HBT technology and act as frequency converters for the high frequency...
This paper presents the capabilities of microwave dielectric spectroscopy for biological cells suspensions analysis. The developed biosensor integrates both microfluidic channel for biological samples manipulation together with a microwave circuit for dielectric spectroscopy. Experimental investigation validates the success and accuracy of the microwave dielectric spectroscopy technique. This technique...
This paper presents the application of the Boundary Integral-Resonant Mode Expansion (BI-RME) method to the modeling of waveguide components comprising lossy dielectric materials. The proposed technique is based on the combination of the BI-RME method and of a perturbation approach. The BI-RME method yields the frequency response in terms of the generalized admittance matrix, expressed as a pole expansion...
For the first time the partial-capacitance and conformal mapping techniques are applied for modeling of the open multiconductor microstrip lines of finite thickness. To build new model, the concept of magnetic slits is introduced, which allows the cross-section multiple connected region to reduce into the simple connected region. The obtained polygonal region is conformal mapped by analytical Schwarz-Christoffel...
The substrate integrated waveguide can easily be integrated with planar microwave circuits. Antennas designed on this transmission line have a planar structure, and can be fabricated by a standard PCB technology, so they are suitable for mass production. This paper presents the results of an investigation of leaky wave antennas designed on a substrate integrated waveguide. The interest is given to...
This paper presents a synthesis method for short-circuited waveguide orthomode transducers (OMTs). An equivalent circuit model of slot-coupled square waveguide T-junction is initially proposed, and useful formulas are derived for synthesis of the single-band OMT. Then a dual-band OMT connected with two filters is further designed using the circuit model and the synthesis theory for a filter matched...
In this article the design and the construction of an ultrawideband (UWB) 3 dB hybrid coupler are presented. The coupler is realized in broadside stripline technology to cover the operating bandwidth 0.5 – 18 GHz (more than five octaves). Detailed electromagnetic design has been carried to optimize performances according to bandwidth. The comparison between simulations and measurements validated the...
A broadband liquid crystal based polarizer is presented in this paper, electrically changing the orientation of the fundamental TE01-mode of a square waveguide. The basic concept is similar to the twisted nematic cell in LC-display technology, however, adapted to the microwave regime as a waveguide component. This allows for continuous, electrical reconfiguration of the linear polarization from −90°...
This work presents a novel class of filters in substrate integrated waveguide (SIW) technology, based on a multilayered configuration. The peculiarity of these filters is the presence of additional poles and zeros, due to the resonant slot etched in the common metal layer between two dielectric substrates. In this way, a filter with two mono-modal cavities, coupled by a resonant slot, exhibits a frequency...
This paper proposes an equivalent circuit model of carbon nanotubes (CNTs) films dropped on demand by inkjet printing and using low cost paper substrate. The CNTs are printed in gap of the central line of coplanar waveguides used as test structures. The proposed model was validated by experimental measurement. The suggested equivalent model can be exploited in the implementation of different inkjet-printed...
This paper presents a novel compact, UHF-band lumped element filter that shows good results versus other similar designs, with a 20% fractional bandwidth operating at 500MHz with a 17dB return loss. The circuit was designed using multilayer LCP, with a focus on minimising the footprint and the number of vias present, which was achieved by folding the design and implementing a block of shared ground...
A 270-GHz reflection-type push-push oscillator is presented, realized using 0.8µm emitter InP-DHBTs. The InP DHBT-on-BiCMOS offers both InP HBT and BiCMOS technologies but in this case only the InP part is used. The transistors exhibit a maximum oscillation frequency fmax of 300 GHz. The oscillator delivers −9.5 dBm output power. DC consumption is only 31 mW from a 1.8 volts power supply, which corresponds...
Many authors have published methods to synthesize microwave filters that provide a circuit prototype composed of ideal resonators and ideal couplings between them. Usually, the implementation step of that network with a particular technology is provided with few details. This work presents a method to synthesize a rectangular waveguide filter with transmission zeros designed by the extracted pole...
The space mapping technique is used to correct manufacturing tolerances related to the production of circular-waveguide dual-mode filters. The tuning screws placed inside each cavity are replaced by fixed square insertions that can be fabricated in separated pieces. A series of these insertion pieces are designed following a space mapping technique, and are then fabricated, thus being able to progressively...
In the last years, the development of broadband microwave sensors for cell detection has become a great challenge. In this work, a broadband microchamber integrated with microfluidics is used for cell detection in the GHz range. Measurements of scattering parameters have been carried out, demonstrating the capability of the device to discriminate different number of cells between the electrodes. Stable...
A low cost, fully planar tunable oscillator with a low phase noise, high DC-RF conversion efficiency for C-band is presented in this work. The proposed oscillator utilizes a novel complementary coupled resonator based on substrate integrated waveguide (SIW) that has a broad tuning range of 8.84% relative bandwidth, and thereby achieves a continuous tuning oscillation range from 4.85 GHz to 5.1 GHz,...
This paper reports a compact high power oscillator operating from 2.3 GHz to 2.9 GHz. Its two differential outputs deliver up to 57 W of power with an efficiency peaking at 54 %. A phase noise of −125 dBc / Hz is achieved at 1 MHz offset frequency. The oscillator is realized as a hybrid circuit with two GaN HEMTs. Including the housing, it fits in an area of less than 13 cm2.
More than fifty years ago I was involved into research and development of microwave circuits based on the waveguide technology. At the beginning of my work I had the opportunity to be visiting researcher at the Polytechnic Institute of Brooklyn. During my stay there I heard about the book entitled: “Microwave filters, impedance-matching networks, and coupling structures”. I felt that was the book...
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