Planar compact, broad‐stopband elliptic‐function lowpass filters using high‐permittivity ceramic substrate

Abstract

design and also in fabrication, the resultant CP is not pure, corresponding a finite cross-polar level.The simulated and measured radiation patterns are shown in Figure 5. For the designed sample, the measured results of Ϫ26-dB cross-polar level, Ϫ13-dB side-lobe level, ϳ13.5°half-power beamwidth, and 17.3-dBi gain corresponding to ϳ40% aperture efficiency are obtained. The bandwidth for cross-polar level less than Ϫ15 dB excesses 8%. Hence, the precise polarized variability by adjusting and ␣ in a relatively broad band can be expected. CONCLUSIONIn this paper, a novel broadband reflectarray with variable polarization has been proposed, and the principle of polarized variability has been analyzed in detail and also verified by simulation and experiment. The mechanism of polarized variability is quite simpler than a traditional antenna with complex feed network; only the operation of mechanical rotation is needed. This reflectarray presents good features of broadband and higher gain (with a great number of elements), and has potential significance for engineering application.ABSTRACT: The miniaturization of hairpin lowpass filters by employing two high-permittivity ceramic substrates (with respective dielectric constants of 9.7 and 22.6) are investigated. Microwave dielectric ceramics with high permittivity are commonly applied in several microwave communication components. With the advantages of compact size, high-permittivity ceramics can be used as the substrate for low-pass filters. Moreover, the fundamental characteristics of newly developed compact stepped-impedance hairpin resonators with parallel coupled lines have also been described and applied to the design of lowpass filters. In this paper, the designed multiple cascaded stepped-impedance hairpin resonators structures are simulated using an IE3D simulator. The responses of the fabricated filters using Al 2 O 3 ( r ϭ 9.7, Q ϫ f ϭ 350,000 GHz) and 0.2 Ca 0.6 La 0.26 TiO 3 -0.8Mg 0.95 Co 0.05 TiO 3 ( r ϭ 22.6, Q ϫ f ϭ 57,000 GHz) ceramic substrates are designed at a cutoff frequency of 1.8 GHz. This compact, low-loss, sharp cutoff-frequency response, and broad-stopband lowpass filter should be useful in many wireless communication systems.ABSTRACT: In this paper, chirped fiber Bragg gratings (CFBGs) are proposed as signal-phase controllers for microwave-photonic wireless downstream fiber links. The effect of high-order modulation optical sidebands that disturbs the output mm-wave signal due to the chromatic dispersion induced by the gratings is studied theoretically and experimentally. The 1 st and 2 nd mm-wave harmonics of the output signal have been measured for conventional intensity modulation and for intensity modulation with optical carrier suppression. In the last case, data transmission at 2.5 Gb/s is demonstrated through a chirped grating of 280 ps/nm dispersion in a 40-GHz modulated link.

Using high permittivity ceramic substrates to fabricate a miniaturized bandpass filter with capacitive load

“…However, further miniaturization becomes more difficult for this filter. Planar filters using high-permittivity ceramic substrate, such as parallel-coupled filter [2], interdigital filter [3], combline filters [4], and hairpin filter [5][6][7][8][9], provide good miniaturization ability. Generally speaking, a conventional half-wavelength open-line microstrip resonator is too large to be used in modern communication systems such as personal communication systems at 900 and 1800 MHz, and wireless location area networks at 2.4 and 5.3 GHz [2].…”

“…It has been demonstrated that CSRR etched in the ground plane or in the conductor strip of planar transmission media (microstrip or CPW) provide a negative effective permittivity to the structure. CSRR has been successfully applied to the narrow band filters and diplexer with compact dimensions [7,8].…”