75,409 research outputs found
Multimode synthesis procedure for microwave filters based on thick inductive windows
For several types of microwave filters for space application it is important to manufacture hardware without tuning elements. For this to be possible, one needs a systematic procedure to codvert ideal elements, such as resonators and impedance inverters, into actual waveguide lengths and discontinuities. The situation is further complicated by the fact that waveguide discontinuities excite higher order modes that interacting with each other can have very strong effects. In this paper we first outline the theory behind a very efficient computer code for the simulation of microwave filters based on thick inductive windows. Then we describe in detail a step-by-step procedure that, based on the code developed, allows for the rapid design of this class of microwave filters without any tuning elements. Two actual examples of design are also discussed and comparisons presented between measurements and simulations
Photonic RF and microwave reconfigurable filters and true time delays based on an integrated optical Kerr frequency comb source
We demonstrate advanced transversal radio frequency (RF) and microwave
functions based on a Kerr optical comb source generated by an integrated
micro-ring resonator. We achieve extremely high performance for an optical true
time delay aimed at tunable phased array antenna applications, as well as
reconfigurable microwave photonic filters. Our results agree well with theory.
We show that our true time delay would yield a phased array antenna with
features that include high angular resolution and a wide range of beam steering
angles, while the microwave photonic filters feature high Q factors, wideband
tunability, and highly reconfigurable filtering shapes. These results show that
our approach is a competitive solution to implementing reconfigurable, high
performance and potentially low cost RF and microwaveComment: 15 pages, 11 Figures, 60 Reference
Microwave Components with MEMS Switches
RF MEMS switches with metal-metal contacts are being developed for microwave applications where broadband, high linearity performance is required. These switches provide less than 0.2 dB insertion loss through 40 GHz. This paper describes the integration of these switches into selected microwave components such as reconfigurable antenna elements, tunable filters, switched delay lines, and SPDT switches. Microwave and millimeter wave measured results from these circuits are presented
Application of Memristors in Microwave Passive Circuits
The recent implementation of the fourth fundamental electric circuit element, the memristor, opened new vistas in many fields of engineering applications. In this paper, we explore several RF/microwave passive circuits that might benefit from the memristor salient characteristics. We consider a power divider, coupled resonator bandpass filters, and a low-reflection quasi-Gaussian lowpass filter with lossy elements. We utilize memristors as configurable linear resistors and we propose memristor-based bandpass filters that feature suppression of parasitic frequency pass bands and widening of the desired rejection band. The simulations are performed in the time domain, using LTspice, and the RF/microwave circuits under consideration are modeled by ideal elements available in LTspice
The Beauty of Symmetry: Common-mode rejection filters for high-speed interconnects and balanced microwave circuits
Common-mode rejection filters operating at microwave frequencies have been the
subject of intensive research activity in the last decade. These filters are of interest for
the suppression of common-mode noise in high-speed digital circuits, where differential
signals are widely employed due to the high immunity to noise, electromagnetic
interference (EMI) and crosstalk of differential-mode interconnects. These filters can
also be used to improve common-mode rejection in microwave filters and circuits
dealing with differential signals. Ideally, common-mode stopband filters should be
transparent for the differential mode from DC up to very high frequencies (all-pass),
should preserve the signal integrity for such mode, and should exhibit the widest and
deepest possible rejection band for the common mode in the region of interest.
Moreover, these characteristics should be achieved by means of structures with the
smallest possible size. In this article, several techniques for the implementation of
common-mode suppression filters in planar technology are reviewed. In all the cases,
the strategy to simultaneously achieve common-mode suppression and all-pass behavior
for the differential mode is based on selective mode-suppression. This selective mode
suppression (either the common or the differential mode) in balanced lines is typically
(although not exclusively) achieved by symmetrically loading the lines with symmetric
resonant elements, opaque for the common-mode and transparent for the differential
mode (common-mode suppression), or vice versa (differential-mode suppression).MINECO, Spain-TEC2013-40600-R, TEC2013-41913-PGeneralitat de Catalunya-2014SGR-15
Novel design procedure for microwave filters
In this paper a novel design procedure is described for the hardware implementation of microwave filters. The procedure is
based on a very accurate and efficient software package for the full-wave simulation of the structure and consists of a step-by-step procedure that systematically leads to dimensioning of the mplete filter geometry. Following the procedure described, each
successive step only involves the dimensioning of a maximum of four physical parameters. As an illustrative example, the design of a nine pole non-uniform filter is discussed indicating how the procedure is indeed very efficient
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