Five-pole Bandpass Filter Research Articles

High selectivity wideband bandpass filters based on flexibly transferring the structure of a coupled-line

Two novel high selectivity wideband bandpass filters (BPFs) based on flexibly transferring the structure of a coupled-line are proposed in this paper. More flexible design and more widely used scenarios are obtained due to the transformational structure of a coupled-line. An open coupled-line and a transmission line connecting the input port bring the wide bandwidth and the great frequency selectivity to BPF Ⅰ. The proposed BPF Ⅱ realizes two transmission zeros close to the passband by a stepped-impedance stub. The generalized theoretical analysis of the two asymmetric BPFs is presented. Two five-pole BPFs both working in the 3.5-GHz band with two transmission zeros on each side of the passband are simulated, fabricated, and measured to demonstrate the feasibility of the design. The 3-dB fractional bandwidths (FBWs) of the two BPFS are 73.17% and 78.34%, separately. Good consistencies are observed between the simulated and measured results.

Direct synthesis approach for designing high selectivity microstrip distributed bandpass filters combined with deep learning

This paper presents a direct synthesis and design method based on modified Chebyshev function for high-selectivity wideband bandpass filters (BPFs). This method can synthesize high-order filters with sharp selectivity without requiring complex topologies. Out-of-band rejection of the synthesized filters can be controlled by introducing or removing transmission zeros at finite frequencies. A structure parameter estimation method based on the neural network is used to optimize the structures of BPFs, eliminating the tedious work of manual optimization. The designed bandpass lumped circuits are transformed into distributed circuits accurately by being divided into four basic blocks. In order to prove the performance of the proposed function and the validation of the theory, a five-pole BPF and a nine-pole BPF were designed and measured, proving the practicability of the proposed method.

Design Procedure for Bandpass Filters Based on Integrated Coaxial and Rectangular Waveguide Resonators

In this article, we present a novel bandpass filter based on dual-mode resonators. The dual-mode operation is based on integrated coaxial and rectangular waveguide cavities. Furthermore, we also discuss a systematic design procedure for the selection of the dimensions of the various constituent elements of the filter, which is based on the well-known aggressive space mapping technique. The design of a five-pole bandpass filter operating in the X-band is discussed in detail, including the measured data. The comparison between simulations and measurement shows very good agreement, thereby fully validating both the new filter structure and the design procedure.

A +14.2 dBm, 90–140 GHz Wideband Frequency Tripler in 250-nm InP DHBT Technology

A single-chip active frequency tripler circuit with output at F-band (90–140 GHz) is presented. A common-emitter transistor stage with input and output matching circuits is used to produce the third harmonic, followed by a five-pole band-pass filter and a wideband four-stage power amplifier to amplify and increase the output power. The circuit is implemented in a 250-nm InP double-heterostructure bipolar transistor technology with ft/fmax 350/650 GHz, respectively. The chip achieves a peak output power of 14.2 dBm from 99 to 126 GHz at 2-dBm input power and conversion gain of 13 dB at −2-dBm input power. The measured 3-dB output bandwidth is 51 GHz from 90 to 141 GHz which corresponds to 44.2% relative bandwidth. It demonstrates up to 23-dBc rejection ratio of the first and the second harmonics. The dc power consumption is 156 mW at 2-dBm input power. The chip size is $0.9 \times 0.96\,\,\text {mm}^{{2}}$ including pads and achieves a power efficiency of 16.7%.

Synthesis and Design of High-Selectivity Wideband Quasi-Elliptic Bandpass Filters Using Multiconductor Transmission Lines

A comprehensive study of high-selectivity filters that employ series multiconductor transmission lines (MTLs) and a shunt MTL is presented. It is shown that this topology is suitable for implementing three- and five-pole bandpass filters having a quasi-elliptic frequency response. An exact synthesis procedure with analytical design equations for achieving equal-ripple passband response as a function of the operating bandwidth is described. To validate the theory, several bandpass filters are designed, fabricated, and measured. The excellent agreement between the measurements and the predicted results validates the proposed procedure as a reliable and quick technique for designing wideband quasi-elliptic bandpass filters.

Miniature ridge-waveguide filter module employing moldable dielectric material

The experimental 6-8.6-GHz five-pole bandpass filter being presented is composed of ridge-waveguide resonator segments, evanescent-mode inter-resonator coupling sections, and planar-circuit impedance-matching port networks. To reduce overall filter size, cavities are filled with a low-loss moldable dielectric material that does not shrink during curing. Good agreement is observed between measured and predicted filter response characteristics. Two additional bandpass filter designs with different fractional bandwidths further highlight the versatility of the design methodology that relies entirely on the use of commercially available general-purpose design software.

Highly integrated millimeter-wave passive components using 3-D LTCC system-on-package (SOP) technology

In this paper, we demonstrate the development of advanced three-dimensional (3-D) low-temperature co-fired ceramic (LTCC) system-on-package (SOP) passive components for compact low-cost millimeter-wave wireless front-end modules. Numerous miniaturized easy-to-design passive circuits that can be used as critical building blocks for millimeter-wave SOP modules have hereby been realized with high-performance and high-integration potential. One miniaturized slotted-patch resonator has been designed by the optimal use of vertical coupling mechanism and transverse cuts and has been utilized to realize compact duplexers (39.8/59 GHz) and three- and five-pole bandpass filters by the novel 3-D (vertical and parallel) deployment of single-mode patch resonators. Measured results agree very well with the simulated data. One multiplexing filter, called the directional channel-separation filter, that can also be used in mixer applications shows insertion loss of <3 dB over the bandpass frequency band and a rejection /spl sim/25 dB at around 38.5 GHz over the band-rejection section. LTCC fabrication limitations have been overcome by using vertical coupling mechanisms to satisfy millimeter-wave design requirements. Lastly, a double-fed cross-shaped microstrip antenna has been designed for the purpose of doubling the data throughput by means of a dual-polarized wireless channel, covering the band between 59-64 GHz. This antenna can be easily integrated into a wireless millimeter-wave link system.

Design of an interdigital hairpin bandpass filter utilizing a model of coupled slots

A design methodology of an interdigital hairpin filter based on a full-wave model of coupled slots is developed and discussed. It is applied to design a five-pole bandpass filter centered at 1.7 GHz; with 1.75% relative bandwidth. A low level of in-band insertion loss is achieved using high-temperature superconductor electrodes. Experimental data are presented and compared with the simulated response. A model of coupled slots embedded in a layered lossy media is developed on the basis of the spectral-domain approach. The multiport admittance (impedance) matrix of the coupled slots is formulated using the E-H duality principle. It is successfully applied in the design of the filter.

Nonlinear surface impedance of YBCO thin films: Measurements, modeling, and effects in devices

High-Tc thin films continue to be of interest for passive device applications at microwave frequencies, but nonlinear effects may limit the performance. To understand these effects we have measured the nonlinear surface impedanceZs in a number of YBa2Cu3O7−x thin films as a function of frequency from 1 to 18 GHz, rf surface magnetic fieldHrf to 1500 Oe, and temperature from 4 K toTc. The results at lowHrf are shown to agree quantitatively with a modified coupled-grain model and at highHrf with hysteresis-loss calculations using the Bean critical-state model applied to a thin strip. The loss mechanisms are extrinsic properties resulting from defects in the films. We also report preliminary measurements of the nonlinear impedance of Josephson junctions, and the results are related to the models of nonlinearZS. The implications of nonlinearZS for devices are discussed using the example of a five-pole bandpass filter.