Dpto. Ingeniería Eléctrica, Electrónica y de Comunicación - Ingeniaritza Elektriko eta Elektronikoaren eta Komunikazio Ingeniaritzaren Saila [desde mayo 2018 / 2018ko maiatzetik]

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Dpto. Ingeniería Eléctrica y Electrónica - Ingeniaritza Elektriko eta Elektronikoa Saila



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Browsing Dpto. Ingeniería Eléctrica, Electrónica y de Comunicación - Ingeniaritza Elektriko eta Elektronikoaren eta Komunikazio Ingeniaritzaren Saila [desde mayo 2018 / 2018ko maiatzetik] by Author "Ahmad, Jamil"

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    PublicationOpen Access
    Enhancement of the peak power handling capability in microstrip filters by employing smooth-profiled conductor strips
    (2023) Ahmad, Jamil; Hussain, Jabir; Arregui Padilla, Iván; Martín Iglesias, Petronilo; Arnedo Gil, Israel; Gómez Laso, Miguel Ángel; Lopetegui Beregaña, José María; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
    This paper presents a design methodology that significantly increases the peak power handling capability (PPHC) of microstrip filters. The PPHC is limited in microstrip technology by the corona effect: a physical phenomenon caused by the ionization of the air under the presence of strong electric fields around the planar circuit. Microstrip filters with a low electric field strength in the air increases the corona threshold level, resulting in high PPHC. Conventional stepped impedance (SI) filters, which consist of cascaded step-shaped elements, exhibit sharp discontinuities. These geometric edges amplify the electric field strength in the air, consequently reducing the corona threshold. Our research group has recently reported a new synthesis technique that introduces a smooth-profile (SP) conductor strip. This SP strip eliminates any sharp discontinuities and significantly reduces the strength of the electric field. This paper focuses on the examination of the high power performance of 7th-order SP and SI low-pass filters. The cut-off frequency (fc) for both types of filters is set at 447.45 MHz, while the frequency for maximum stop-band rejection (fo) is 1 GHz. The findings indicate that the SP filter shows a notable enhancement in peak power handling capability (PPHC), with gains of 2.48 dB and 4.80 dB observed at critical pressure and ambient pressure, respectively.
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    PublicationEmbargo
    High-frequency passive components and filters for future high-capacity space and ground communication systems in a hyper-connected world
    (2023) Ahmad, Jamil; Lopetegui Beregaña, José María; Arnedo Gil, Israel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
    This Ph.D. thesis presents the design and fabrication of microwave filters in microstrip and coaxial technologies. The filters are designed using a novel synthesis technique based on coupled mode theory and inverse scattering techniques, resulting in smooth-profiled filters with improved performance characteristics. These filters are particularly well suited for high-power applications, such as satellite-based communication systems. Satellite RF payloads heavily rely on microwave filters, necessitating robust designs with small footprints and high power handling capabilities for both peak and average power. Traditional filter design methods face limitations when operating across wide frequency bands and achieving sufficient power handling capabilities. The proposed novel synthesis technique offers a general and flexible approach to design smooth-profiled filters, overcoming the drawbacks of conventional design techniques. The core of the novel synthesis technique lies in the coupled mode theory, which characterizes the electromagnetic behavior of non-uniform structures, like smooth-varying microwave filters. The technique involves determining coupling coefficients related to the physical dimensions of the structure through coupled-mode equations. Using this innovative synthesis technique, several smooth-profiled filters are designed in microstrip and coaxial technologies, for different frequency specifications. For microstrip filters, in addition to conventional substrates, non-conventional substrate is also explored. The non-conventional substrate is manufactured layer-by-layer using stereolithography (SLA) with a resin filled with ceramic material. Subsequently, silver nanoparticles are deposited on the ceramic substrate using Aerosol Jet Printing (AJP). The validity of the novel synthesis method and the fabrication technique is thoroughly demonstrated through a comprehensive comparison of theoretical, simulated, and measured results, showing a high degree of agreement between them. Overall, this thesis contributes to the advancement of microwave filter design for satellite communication systems, offering a promising approach to achieve enhanced performance, improved power handling, and reduced manufacturing costs through an innovative synthesis technique and novel fabrication processes.
  • Thumbnail Image
    PublicationOpen Access
    Improvement of corona breakdown threshold (peak power handling) in smooth-profiled microstrip filters
    (2022) Ahmad, Jamil; Hussain, Jabir; Arregui Padilla, Iván; Martín Iglesias, Petronilo; Arnedo Gil, Israel; Gómez Laso, Miguel Ángel; Lopetegui Beregaña, José María; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
    In this paper, the PPHCs of two filter design techniques, stepped-impedance (SI) and smooth-profile (SP), are presented for four design prototypes. Smooth-profiled filters feature smooth variations in the characteristic impedance profile, avoiding sharp edges, which accumulate electric fields. The absence of sharp edges in SP reduces the voltage magnification factor, which in turn improves the PPHC of the filter. The phenomenon of electric fields accumulation at the sharp corners of the SI filters is presented and compared with smooth transitions in SP filters. Furthermore, 1D graphs of electric field intensity are presented along the strip contour of the microstrip lines. Finally, SPARK3D results clearly demonstrate that SP filters can handle higher peak powers than their SI counterparts between critical pressure and ambient pressure, for all the studied designs.