Microstrip Slow-wave Structures Research Articles

Investigation and Experiment of a Novel Chamfered V-Shaped Microstrip Slow-Wave Structure for W-Band Traveling-Wave Tube

Investigation and Experiment of a Novel Chamfered V-Shaped Microstrip Slow-Wave Structure for W-Band Traveling-Wave Tube

Research and Development of Traveling Wave Tubes with Planar Microstrip Slow-Wave Structures on Dielectric Substrates

Research and Development of Traveling Wave Tubes with Planar Microstrip Slow-Wave Structures on Dielectric Substrates

Magnetron co-sputtered μm-thick Mo–Cu films as structural material with low heat extension for key parts of high-power millimeter-band vacuum microelectronic devices

The development of high-power millimeter and THz-band vacuum microelectronic devices (μVEDs) demands structural materials with special properties. In particular, key components of μVEDs must retain their dimensions when heated while operating at higher power levels. A molybdenum-copper alloy is a promising material, thanks to the low thermal expansion of molybdenum and the remarkable thermal and electrical conductivity of copper. However, such alloys can only be obtained by a limited number of techniques that are rather complicated. Thus, the goal of this work is the implementation of vacuum magnetron co-deposition as a facile method in the fabrication of μm-thick Mo–Cu films. Such films are very promising for the microfabrication of microstrip slow-wave structures for high-power millimeter and THz-band μVEDs. This study is focused on controlling the morphology, resistivity, and roughness of the fabricated thin films by changing the deposition process parameters, such as the sputtered Cu and Mo ratio and substrate temperature.

Development of microfabricated planar slow-wave structures on dielectric substrates for miniaturized millimeter-band traveling-wave tubes

We report the results of the design, simulation, fabrication, and cold-test measurements of millimeter-band 2D planar microstrip slow-wave structures (SWSs) on dielectric substrates. Such structures have a high slow-wave factor, which allows for low-voltage operation and reduction in the size and weight of the device. A low-cost and flexible fabrication technology based on magnetron sputtering and subsequent laser ablation has been developed and is reported in the paper. Microstrip meander-line SWS circuits at V-, W-, and D-bands have been fabricated and characterized. The fabrication of ring-bar planar SWSs by the photolithographic method is also discussed. Experimental measurement of S-parameters of the fabricated structures reveals good transmission properties. Return loss (S11) does not exceed −10 dB and attenuation is about 2 dB/cm in the V-band, 10 dB/cm in the W-band, and 8.5 dB/cm in the D-band.

Design and Cold Test of Dual Beam Azimuthal Supported Angular Log-Periodic Strip-Line Slow Wave Structure

A novel Ka-band azimuthal supported angular log-periodic strip-line (ASALS) slow wave structure (SWS) is proposed for a miniature radial sheet beam traveling wave tube (TWT). In the proposed SWS, two dielectric rods are employed to support the ASALS at both azimuthal sides. The strip-line is made of high-melting metal; thus, the ASALS SWS has a higher power capacity than microstrip SWSs. The high-frequency characteristics of that proposed SWS are investigated by using simulation software. The ASALS SWS is then fabricated and assembled for cold test. The measured transmission loss and reflection loss are better than − 2.5 dB and − 10 dB, respectively. The hot performance of the proposed is studied based on particle-in-cell (PIC) simulation. It is shown that when the operating voltage is 5700 V, the ASALS TWT can give a maximum output power of 320 W at the frequency of 39 GHz, corresponding to a gain of 14.9 dB and electron efficiency of 9.12%.

A High Slow-Wave Factor Microstrip Structure With Simple Design Formulas and Its Application to Microwave Circuit Design

This paper proposes a new microstrip slow-wave structure. The unit cell comprises a Schiffman section of meander line and a shunt open-circuited stub. No via-holes and ground-plane patterns are required. Simple design formulas can be used to obtain line parameters, such as the characteristic impedance and phase velocity. According to the analysis, the characteristic impedance and slow-wave factor of the proposed slow-wave line can be independently controlled by merely two layout parameters. The proposed uniplanar structure only requires a single-layer substrate and is simply constructed using the conventional printed circuit board manufacturing process. A branch-line and a rat-race coupler were designed and fabricated using the proposed structure to demonstrate its feasibility. Their sizes are only 8.49% and 4.87% of the conventional ones, respectively. This novel slow-wave structure should find wide applications in compact microwave circuits.

Novel Microstrip Periodic Structure and Its Application to Microwave Filter Design

This letter proposes a new type of microstrip slow-wave structure. The proposed structure has the signal strips and the inserted ground strips periodically loaded in the internal part of the conventional microstrip line. The proposed microstrip line has not only the same outline contour but also a lower phase velocity compared to the conventional one, especially for the thick substrate. In addition, the slow-wave factor and the characteristic impedance are easily varied by adjusting the structural parameters. A third-order Chebyshev filter with a passband ripple of 0.05 dB and a bandwidth of 10% was designed and fabricated using the proposed microstrip line. The simulated and measured results agree well with each other.

Uniplanar microstrip periodic structure for microwave circuits

A novel microstrip slow-wave structure is presented. The slow-wave factor is mainly controlled by the signal strip and the inserted ground metal pattern in a coplanar manner. A third-order Chebyshev filter was designed and fabricated to demonstrate the proposed structure. Good agreement between the simulated and measured responses is observed.

Compact power divider embedded with zigzag microstrip slow-wave structures

A novel zigzag microstrip slow-wave structure is presented, which effectively reduces the occupied length to 34% of a normal microstrip structure. A sample power divider using the slow-wave structure is given, the whole size of the proposed divider has been reduced by 39% compared to a conventional power divider. The design is validated both by simulation and by measurement.

A new type of slow‐wave 1‐D PBG microstrip structure without etching in the ground plane for filter and other applications

AbstractA new type of one‐dimensional (1D) photonic bandgap (PBG) microstrip slow‐wave structure applied for filter is presented. The proposed filter exhibits remarkable slow‐wave and low‐pass characteristics. It is formed without etching in the ground plane, only by modification of the microstrip line. The miniature low‐pass filter with three cells is simulated, realized, and measured. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 440–443, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10345