1,721,035 research outputs found
Advantages and Limitations of a Polynomial Approach to the Design of Compact Multiplexers
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Three-Step Monoblock Waveguide Twist
No full textTwists are widespread devices among waveguide systems and assemblies. Their usefulness lies into the chance to interconnect sections with different orientation angles. Twists are often integrated directly into dual polarization systems, multiplexers and antenna feeds. Performance, compactness and costs are usually in trade-off but all of them need to be privileged to deliver a successful waveguide-based system. The novel approach proposed in this manuscript deals with the manufacturing of a wideband gradual rotation by means of three sections which can however be carved from a metallic monoblock through very standard milling process. This achievement is based on geometrical observations and on CNC milling procedures. The proposed concept is then verified with a 90° twist based on standard WR75 with promising performance in terms of matching and losses
Narrowband Microwave Filters With Mixed Topology
No full textNarrowband microwave filters exhibiting transmission zeros in the response (either imaginary and/or complex) can be typically designed with cross-coupled or extracted pole topologies. These configurations have advantages and disadvantages that must be carefully considered during the choice of a specific topology. In some cases, however, it may be convenient to choose a mixed topology, i.e., part of the structure with an extracted-pole and part with a cross-coupled configuration. Unfortunately, even if several well-established techniques are available in the literature for the cross-coupled or extracted-pole synthesis taken separately, nothing can be found for the design of mixed topology filters (apart direct optimization). In this study, two solutions for the synthesis of a low-pass prototype with a mixed topology are presented, which noticeably increases the design flexibility of narrowband microwave filters. Several examples are presented for illustrating the proposed techniques for the synthesis of mixed-topology prototype filters. A test filter, synthesized with the second method introduced and fabricated in coaxial technology, has given an experimental validation of the proposed techniqu
Bandpass filter with multiple selective absorptive stopbands for 28 GHz transmitters
No full textThis manuscript presents a novel design for an absorptive bandpass filter for mm-wave applications, specifically the commercial FR2 spectrum. Three bands have been selected to be properly input matched with only one of them being the passband, where the insertion loss is minimized. The proposed approach relies on a multiplexer topology implemented through microstrip lines and on thin-film manufacturing process on alumina to shrink the footprint. Cascades of half-wavelength C-shape open-ended resonators are exploited to create the matched bands and define the filter's selectivity. The selected passband spans from 26.5 to 28.5 GHz, with a measured maximum insertion loss of 3.05 dB for a -3 dB fractional bandwidth of 7.3%. Two absorptive bands are realized to match signals at 24 and 32.25 GHz. The alumina die footprint is 5500 x 3440 mu m2, compatible with immediate integration within a mm-wave lineup
Synthesis of Simplified Cross Coupled Blocks with All Positive Couplings
No full textThis paper introduces a new resonant coupling structure for inline rectangular waveguide filters. The proposed structure consists of a rectangular cavity placed on top of the main waveguide, and it exploits the TE 102 mode for creating a frequency-variant coupling capable of producing one transmission zero (TZ). An equivalent circuit characterized by the frequency of the TZ and the slope parameter X eq of the proposed stopband was used in order to realize a filter straightforwardly. Since no internal elements produce any discontinuities, very high values of the X eq are achievable, which allows for placing the TZ closer to the passband while still proving high Q-factors. The design of a 4-pole with a TZ in the upper stopband is illustrated, and the filter was fabricated and measured for validation purposes
Synthesis of Lossy Filters without the Use of the Coupling Matrix
No full textThis paper describes a synthesis method based on an
even- and odd-mode decomposition capable of synthesizing a prescribed pair of transmission and reflection functions with very few additional constraints. Then it is also shown an analytical method to evaluate the characteristic polynomials of a lossy filter based on the exploitation of the degrees of freedom available in a lossy design.
This method can be used in conjunction with the proposed
synthesis method to obtain a simple and general procedure suitable for lossy filters
A New Approach to the Synthesis of Microwave Lossy Filters
No full textIn this paper, we first present a novel synthesis method based on an even- and odd-mode decomposition. This method is capable of synthesizing a network under very general hypotheses and is, therefore, suitable for lossy filter design. To exploit the increased flexibility of this new synthesis method over the traditional lossy design techniques, we then introduce a new approach to the design of lossy filters based on the characteristic polynomials evaluation. This new technique can offer many advantages over traditional techniques, and the main one is that, once the transmission function of the filter is known using traditional methods, the reflection function can be constrained with a certain degree of freedom. A tradeoff between additional constraints and redundancy in the final network must be accepted. Finally, we present design examples and a practical realization, which validate this novel approach to the design of lossy filters
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