Mode Bandpass Filter Research Articles

Novel Microstrip Right-Angled Triangular Patch Resonator Bandpass Filter

Dual-mode and multi mode techniques have very important applications for microwave filter design to implement miniaturization and nicer performances of transmission zeros, wide band and so on. This paper presents a new multi mode bandpass filter with wide passband and two kinds of new DC-block dual-mode bandpass filters by using an isosceles right-angled triangular resonator which with much less attention, all have transmission zeros and low passband insertion losses. The new filters have novel, compact and simple structures as well as nicer performances, and are quite useful for modern RF/microwave circuits and systems.

Uniaxial discontinuities analysis by a new multimodal variational method—application to filter design

A new mulitimodal varational formulation (NMVF) is presented for the characterization of cascaded discontinuities in microwave components by using a formal admittance operator of the complete structure. The admittance operator is constructed by using all higher-order modes in intermediate waveguides, so that the convergence study versus the number of modes will no longer be needed, contrary to classical modal decomposition methods. This formulation will theoretically lead to increased accuracy for the overall S parameters. To validate this new approach, a step-discontinuity is analyzed and an evanescent mode bandpass filter is designed. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE 2007.

A dual degenerate mode X‐band bandpass filter in LTCC

AbstractA wideband dual mode bandpass filter at 9.0 GHz with a bandwidth of 20% has been demonstrated in low temperature cofired ceramics (LTCC). A new stacked‐ring resonator (SRR) is proposed and its design methodology as well as analysis is presented in details. The simulated and measured results are in good agreement. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2246–2249, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21917

Artificial Dielectric Rectangular Resonator with Novel Anisotropic Permittivity and Its TE10 Mode Waveguide Filter Application

A miniaturized rectangular resonator made of a novel anisotropic artificial dielectric material is investigated which has advantages of small size and big separation of the higher-modes. To obtain a property of anisotropic permittivity, artificial dielectric material is fabricated by lamination of rectangular metal strips etched on a printed circuit board. Artificial dielectric rectangular resonators are designed to excite TE 10δ mode selectively, aligning the rectangular metal patterns along the direction of the mode electric field line. The resonant frequencies and coupling coefficient of artificial dielectric rectangular resonators encapsulated in a metal waveguide are analyzed theoretically, and compared with the experimental result. As a microwave application, a high selectivity TE 10δ mode bandpass filter (BPF) using two artificial dielectric rectangular resonators is demonstrated. A two-stage BPF with the center frequency of 1.718 GHz, bandwidth of 78 MHz, and insertion loss of 1.3 dB is successfully realized in a rectangular waveguide.

Fabrication of an X-Band Dual Mode Bandpass Filter Using Low Cost FR4 Substrate

SUMMARY The investigation presents a low cost and low insertionloss X-band dual mode bandpass filter (BPF) based on inexpensive com-mercial FR4 substrate. The proposed filter at a central frequency f 0 of11.3GHz has high filter performance filter with a fractional bandwidth of14%, the insertion loss of −2.7dB, and two transmission zeros. The de-signed procedures are presented in this letter and the fabricated filter veri-fies the proposed designed concept. key words: dual-mode, transmission zero, ring resonator, FR4 1. Introduction Miocrowave communication systems are expanding rapidlyto higher frequency such as C-band or X-band since they canprovide many advantages over conventional wireless links,for example the larger bandwidth and smaller device size.Waveguide components are widely used at these frequenciesand offer very good performance. However, they result inhigh production costs and bulky systems. Conventional pla-nar filter structures suffer from radiation from the resonatorsinto the substrate and from high ohmic loss, and there-fore give high insertion loss and poor filter rejection. Re-cently, the micromachined techniques have been providedand shown to enhance filter performance by removing thedielectric material up to a thin membrane that suspends theplanar filters, therefore reducing of the radiation, ohmic,and dielectric losses of resonators [1],[2]. However, thereis still a challenge in cost down of the commercial RF mi-cromachined device since the devices are fabricated in thesemiconductor-like process.In this letter, we have succeeded to fabricate an lowcost and low loss X band dual mode BPF by using inex-pensive commercial FR4 GD (Glass-Epoxy Double Sided)substrates with thickness of 0.4mm and original relative di-electric constant e

New second generation current conveyor with reduced parasitic resistance and bandpass filter application

A new design for a class AB second generation current conveyor implemented from bipolar transistors is proposed to considerably decrease the parasitic series resistance R/sub X/. SPICE simulation results, using the nominal parameters for the transistors of the 2 /spl mu/m HF2CMOS technology from SGS THOMSON, are given, with /spl plusmn/2.5-V supplies and I/sub 0/= 300 /spl mu/A, the values of R/sub X/ are 1.3 n for the proposed CCII against 53 /spl Omega/ for the conventional one, as an application example, a voltage mode bandpass filter with Q=90 at f/sub 0/=150 MHz has been implemented from the new conveyor and two surface mounted passive components only.

Low-temperature cofired ceramic (LTCC) ridge waveguide bandpass chip filters

Full-wave mode-matching-based design of generalized ridge waveguide evanescent mode bandpass filters and their transitions for low-temperature cofired ceramic (LTCC) application is described. A modification factor is introduced in the prototype filter design to effectively overcome the filter bandwidth distortion. Design examples are given to demonstrate the validity. An S-band single-ridge waveguide filter and its transitions are simulated and successfully built in LTCC packages. Good agreement between the theory and experiment is obtained, which demonstrates the feasibility of the three-dimensional ridge waveguide filter embedding in LTCC packages. As compared with an LTCC inductive windows waveguide filter realization, the ridge waveguide filter realization shows significant advantages of smaller size and comparable loss. Design consideration and LTCC realization of the low-loss ridge waveguide filter are also provided.

Narrow-band light source with acoustooptic tunable filter for optical low-coherence reflectometry

An electrically-tunable narrow-band light source with no moving parts is constructed for jaggedness-free optical low coherence reflectometry. The source incorporates a double-path acoustooptic tunable bandpass filter module whose two passbands automatically agree to within 0.2 nm during wavelength tuning from 1529-1568 nm. The source emits narrow-band light with an FWHM of 1.8/spl plusmn/0.1 nm, a power of >0 dBm and a suppressed background spectrum. The entire wavelength range can be swept electrically within 100 ms by using a variable RF source.

Full-wave design of spurious free DR TE mode band pass filters

Analytic full-wave analysis and design of direct-coupled dielectric loaded bandpass filters in rectangular waveguide configuration using the TE/sub 10/ mode with a spurious-free response up to twice the operating frequency is described. The filter has no tuning screws and is small in size. Theoretical design of the filter is supported by the experimental results. Superiority of the filter over the inductive window-coupled filter is presented. Practical issues faced while building the filter are discussed. An alternative folded configuration of the filter that allows the implementation of both the canonical elliptic function as well as the Chebychev response is also presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Rapidly-tunable narrowband light source with symmetrical crossing configuration for low coherence reflectometry

A rapidly-tunable narrowband light source is constructed for jaggedness-free low coherence reflectometry. A double-path tunable bandpass filter module whose two passbands automatically agree during wavelength tuning is used in the source. The source can emit narrowband low coherence light with an FWHM of 0.57 nm, a power of >0 dBm, and a suppressed background spectrum, at wavelengths from 1534 to 1560 nm. The entire wavelength range can be swept within 10 ms. The rapid tunability leads to both a reduction in the time required to perform the wavelength averaging of Rayleigh backscatter signals, and an enlargement of fine structures in the mean reflection profiles. >

Dielectric ring resonators loaded in waveguide and on substrate

A rigorous mode matching technique is used to analyze the dielectric ring resonators loaded in a waveguide and on top of a substrate. Variation of several lowest order modes' resonant frequencies as a function of structure parameters is presented and is shown to be helpful for optimization of spurious mode separation. Two-dimensional electric and magnetic field line patterns and three-dimensional field intensity distributions of the ring resonators are plotted and provide information for mode excitation, coupling, and spurious mode suppression. Coupling between two dielectric ring resonators loaded in a metallic cavity are analyzed. The dielectric ring resonators are used to design a C-band elliptic function dual mode bandpass filter employing HE/sub 11/ modes. Experimental results are presented and show excellent agreement with the analytical solutions. >

Macroscopic analysis of electromagnetic waves coupling in CdS

The uniaxial stress-induced coupling of the optical ordinary and extraordinary modes in CdS is quantitatively investigated by analyzing, at room temperature, the transmitted light spectrum of a sample placed between two polarizers crossed along the natural neutral lines. Experiments are performed in the wavelength range 5200–7000 Å under application of a calibrated (&amp;lt;500 bar) uniaxial stress directed at 45° with respect to the C axis. At the near gap isotropic wavelength 5229 Å the phase matching allows energy transfer. It is shown that the high selectivity of the process is due to the fast rotation of the induced neutral lines. Due to the stress-induced splitting, the actual birefringence exhibits a sharp but nonzero minimum, at the isotropic wavelength, which is a linear increasing function of the pressure. Its linear pressure coefficient is measured, 6.3×10−6 bar−1, and this allows a direct calculation of the corresponding elasto-optic coefficient p44 = 9.9×10−2. The frequency dispersion of p44 is investigated near the fundamental absorption edge where it exhibits a broad maximum and a sharp structure. The main characteristics of a coupled mode band-pass optical filter are calculated and briefly discussed. Finally the residual internal strain field in most ’’as-grown’’ crystals is estimated as 1.5×10−5.

Mixed Mode Filters (Short Papers)

Mixed mode bandpass filters are described which utilize alternating TE/sub 011//spl deg/ and TE/sub n11//spl deg/ circular waveguide cavity modes. This novel filter configuration exhibits both excellent unloaded Q and spurious mode response characteristics. The use of mixed resonant modes makes possible the design of microwave filters for both in-line side wall connected cylindrical resonators as well as folded planar filter configurations, whereby cross-coupling between selected resonators can be realized.