Insertion Loss Of Filter Research Articles

Antenna-Filter-Splitter Function Reconfigurable Microwave Passive Device Based on VO2

We designed and fabricated a three-in-one function reconfigurable microwave passive device, which can be functionally reconfigured to operate either as a radiating antenna, bandpass filter, or a two-way T-type power splitter. The device's function reconfigurability is enabled by locally sputtering vanadium dioxide (VO2) phase transition thin films, which adjust the shape of conductor resonance patch and interconnect to electrically connect or isolate copper planar transmission lines and the patch on a sapphire substrate. Controlling the combination of the phases of four VO2 thin-films interconnects effectively matches impedance and guides microwave signals, enabling the device's electromagnetic response to be reconfigured without reconstructing the physical structure. For different functions, the return loss and realized gain of patch antenna are 21 dB and −0.98 dBi at 4.75 GHz, respectively; the insertion loss of bandpass filter is 2.8 dB with bandwidth of 150 MHz (4.66–4.81 GHz); the dividing loss of power splitter is 5.0 dB at 4.7 GHz with power and phase imbalance within ±0.5 dB and ±7° from 4.4 to 5.0 GHz, respectively. Combining three devices in series enables more than 13 types of operation, which are suitable for different microwave systems.

Passband broadening of sub-wavelength resonator-based glide-symmetric SIW filters

Here, we discuss the virtues of glide symmetry for designing low-frequency band-pass periodic filters in substrate integrated waveguide (SIW) technology based on complementary split-ring resonators (CSRRs). Conventional (non-glide) versions of these filters have a narrow passband, due to the fact that this band is below the cutoff frequency of the background waveguide. When glide symmetry is added to the filter configuration, the low-frequency passband is significantly widened, as well as the first stopband. The dispersion properties of both conventional and glide-symmetric periodically loaded waveguides are analyzed and compared with commercial software and an equivalent circuit model. Finally, two prototypes of the proposed glide-symmetric structure have been designed and built, illustrating the potential of this technique to widen the passband and reduce insertion losses of conventional sub-wavelength CSRR-loaded SIW filters.

Design of Broadband Band-Pass Filter with Cross-Coupled Line Structure

This paper presents a broadband band-pass filter with cross-coupled line structure. The cross-coupled line structure is composed of the parallel coupled lines and an open stub. It can be analyzed by the odd- and even-mode method due to its symmetric structure. There are three transmission poles in the passband and two transmission zeros out of passband. Then, the influence of the impedance parameters on the transmission zeros and transmission poles are analyzed. Then, the physical parameters of the proposed band-pass filter are given. And using HFSS for simulation and optimization, the final insertion loss and return loss of filter are obtained. The simulation and measurement results are in good agreement, which validates the design idea.

Insertion Loss of Conductive Concrete Line Filters

Conductive concrete structures have been previously demonstrated to perform electromagnetic shielding that satisfied the shielding effectiveness requirements of military standard 188-125-1. The concrete mixture contains proportions of conductive materials together with taconite aggregate for the absorption of EM energy. This letter describes the conductive concrete filter concept as a lossy transmission line and reports the experimental results achieving broadband insertion loss that exceeds 100 dB.

Design and Optimization of Bidirectional Tunable MEMS All-Silicon Evanescent-Mode Cavity Filter

This article presents a bidirectional electrostatic MEMS tuner that enables active voltage compensation of integrated evanescent-mode cavity-based tunable filters. Unlike conventional tunable resonators tuned by unidirectional electrostatic diaphragms, the bidirectional design can compensate for residual displacement errors. This corrective tuning can successfully counterbalance long-term viscoelastic relaxation commonly found in large-displacement MEMS diaphragms. Consequently, it can significantly improve stability and reliability without introducing fabrication complexity. A detailed RF-MEMS codesign and a specific optimization design flow are also discussed. A proof-of-concept, two-pole filter is fabricated, which demonstrates a measured bidirectional tuning range of 18.9–39.6 GHz. The forward (main) actuation tunes the filter from 21.3 to 39.6 GHz with 120 V, whereas the reverse (corrective) actuation tunes it from 21.3 down to 18.9 GHz with 2 V. The measured filter insertion loss varies from 3.14 to 0.78 dB. The extracted unloaded quality factor is 265–510, which is comparable with the state-of-the-art unidirectional filters of this type.

Power transmission characteristics of EWC-SPUDT SAW filters fabricated for multiplex transmission system of inverter gate drive circuits

To increase the electrical power transmission of surface acoustic wave (SAW) filters for gate drive systems of power conversion circuits, we fabricated unidirectional SAW filters based on a SiO2/Al/Pt/LiNbO3 structure in the frequency range of 380–950 MHz and measured their power durability characteristics. A transversal-type electrode-width-controlled single-phase unidirectional transducer (EWC-SPUDT) design was used to reduce the insertion loss of the SAW filters. Our experimental results showed that the transmitted electric power of the output port exceeded 560 mW, which was sufficient for the gate drive circuits. The results obtained demonstrate the validity of the SiO2/Al/Pt/LiNbO3 structure for the proposed EWC-SPUDT design.

A Band Pass Coupled Line Filter with DGS for Ultra-Wide Band Application

Abstract Systems with ultra-band width make use in wireless scenario which enables information transmission over long range of frequency of small distances with a minimum power and high information rates. An ultra-wide band filter is an important requirement for high-quality signal transmission and reception. Designing a compact UWB filter insertion loss much lower is a very difficult task. A structure with ground defected is defined to be etched periodically or non-periodically, cascaded configuration of a planar transmission line whose ground is defected disturbs the current distributed in the ground. A microstrip ultra-wideband filter is introduced in this paper. The filter includes interdigital feed lines on the upper face of substrate and rectangular-shaped structure defected ground at the bottom. The filter is 26.5 x 7.546 x 1.6 mm3 of dimension. The filter provides excellent passband (from 2.4-14.3 GHz) with a reduced return loss of -21.24 dB and insertion loss of -0.7dB at 6.9 GHz. Simulations are carried using ANSYS HFSS Electromagnetic Solver version 16.2.

Wide-frequency tunable bandpass filter with high-frequency selectivity

ABSTRACTBased on the coupling-compensating technologies, a wide-frequency tunable bandpass filter with high-frequency selectivity has been presented in this paper. The coupling coefficient between a pair of resonator and the external quality can be easily controlled, the constant absolute bandwidth (ABW) and the characteristic of tunable wide-frequency can be achieved by changing the position of varactors. By introducing the source-load cross-coupling circuit, the bandpass filter has two transmission zeros, resulting in high-frequency selectivity for the passband. Moreover, only two varactor diodes have been used in the presented tunable bandpass filter. The measured results show that the tunable filter has an almost constant 3 dB absolute bandwidth of 90 ± 5 MHz from 1.55 GHz to 2.00 GHz. The measured insertion loss of the tunable bandpass filter is between 2.2 dB and 3.3 dB, while the return loss is greater than 10 dB within the tunable center frequencies. The measured results of the fabricated tunable bandpass filter show good agreement with the simulated ones.

Inverse Designed Ultra-compact Broadband High-order Mode Filter

Utilizing the inverse design method of nonlinear direct-binary-search (DBS) optimization algorithm, we designed an ultra-compact broadband high-order mode filter on silicon-on-insulator wafer. The incident TE0 mode is prohibited to pass through the high-order mode filter while the TE1 mode can pass with low insertion loss. The footprint of this mode filter is only 1.56 μm × 2.4 μm. Numerical simulation shows that the insertion loss of this mode filter is lower than 0.26 dB and the extinction ratio is lower than 24.5 dB in the wavelength range from 1500 nm to 1600 nm. The insertion loss at the centre wavelength of 1550 nm is only 0.18 dB.

First Demonstration of Compact, Ultra-Thin Low-Pass and Bandpass Filters for 5G Small-Cell Applications

Package-integrated and ultra-thin low-pass filter (LPF) and bandpass filter (BPF) with footprint smaller than $0.5\lambda _{0}\times 0.5\lambda _{0}\times 0.025\lambda _{0}$ at the operating frequencies of 28- and 39-GHz bands are presented for 5G and mm-wave small-cell application. Such package integration of 5G filters with ultrashort 3-D interconnects allows for low interconnect losses that are similar to that of on-chip filters, but low component insertion loss of off-chip discrete filters. These thin-film filters exhibit a cross-sectional height of $188.5~\mu \text{m}$ and can be utilized either as embedded components or integrated passive devices in module packages. Three topologies of LPF and BPF in total are modeled, designed, and fabricated on precision thin-film buildup layers on glass substrate as a core. Large-area panel-compatible semiadditive patterning (SAP) process is utilized to form high-precision topologies to aid the low-cost fabrication of ultraminiaturized filters. SAP also enables the realization of ultra-thin traces to precisely model high-impedance inductive lines compared to conventional subtractive etching and printing techniques. This results in filters with low insertion loss, low VSWR, and high selectivity. The simulated and measured results of filters show an excellent correlation.

Design of Integrated Millimeter Wave Microstrip Pseudo-Interdigital Band pass Filter Using 0.18μm CMOS Technology

High selectivity design of an improved on-chip band pass filter for 60 GHz millimeter-wave applications using0.18 μm CMOS technology is presented. A new type of miniaturized microstrip bandpass filters with pseudo- interdigital structure without via holes grounded resonators is described. A very compact filter of this type, having a size less than quarter-wavelength by quarter-wavelength at a mid-band frequency of 60 GHz was designed. The adoption of a pseudo- interdigital BPF and utilization of two transmissions zero permits a compact size and high selectivity for the BPF. Besides, two defected ground structure cells are etched under the coupled lines to improve the filter insertion loss. The proposed BPF has the center frequency of 60 GHz, insertion loss of -3.6. dB, a 3dB band width of 8 GHz, and core size 200×500 μm2 with total chip size 500×300 μm2 (including bonding pads

RF Channel-Select Micromechanical Disk Filters-Part II: Demonstration.

This Part II of a two-paper sequence presents fabrication and measurement results for a micromechanical disk-based RF channel-select filter designed using the theory and procedure of Part I. Successful demonstration of an actual filter required several practical additions to an ideal design, including the introduction of a 39-nm-gap capacitive transducer, voltage-controlled frequency tuning electrodes, and a stress relieving coupled array design, all of which combine to enable a 0.1% bandwidth 223.4-MHz channel-select filter with only 2.7 dB of in-band insertion loss and 50-dB rejection of out-of-band interferers. This amount of rejection is more than 23 dB better than a previous capacitive-gap transduced filter design that did not benefit from sub-50-nm gaps. It also comes in tandem with a 20-dB shape factor of 2.7 realized by a hierarchical mechanical circuit design utilizing 206 micromechanical circuit elements, all contained in an area footprint of only [Formula: see text]. The key to such low insertion loss for this tiny percent bandwidth is Q 's >8800 supplied by polysilicon disk resonators employing for the first time capacitive transducer gaps small enough to generate coupling strengths of Cx/Co ∼ 0.1 %, which is a 6.1× improvement over previous efforts. The filter structure utilizes electrical tuning to correct frequency mismatches due to process variations, where a dc tuning voltage of 12.1 V improves the filter insertion loss by 1.8 dB and yields the desired equiripple passband shape. Measured filter performance, both in- and out-of-channel, compares well with predictions of an electrical equivalent circuit that captures not only the ideal filter response, but also parasitic nonidealities that distort somewhat the filter response.

Compact microstrip lowpass‐bandpass diplexer using radial stubs

AbstractIn this work, a compact microstrip lowpass‐bandpass diplexer using radial stubs (RSs) is proposed. By controlling the input impedance of the RS resonators, it is possible to obtain a selective lowpass filter (LPF) and a narrow bandpass filter (BPF) with a fractional bandwidth of 5%, without increasing the insertion losses (ILs) of both filters. The design methodology is explained in details and verified through the design of a diplexer achieving very low IL, 0.15 dB for the LPF and 1.2 dB for the BPF. Moreover, the isolation between the ports is 25 dB making the proposed diplexer useful for designing mixer circuits. Experimental results exhibit high correlation with EM simulation data validating the proposed methodology.

Modeling the Insertion Losses of Dielectric Resonators in Microwave Filter Designs

Modeling the insertion losses of microwave filters with dielectric resonators is based on calculating forced oscillations of polarization currents (their amplitudes and phases in the range frequencies) for different designs of microwave filters (e.g., stop-band and pass-band). Knowing the distribution of insertion losses in individual sections of a filter allows us to determine the transfer of heat by dielectric resonators in a vacuum or otherwise.

RF MEMS Based Tunable Bandpass Filter For X-Band Applications

In this paper, we present the design and simulation of RF MEMS based Tunable combline band pass filters for X-band applications at different substrate thicknesses and studied the effect of thickness on tuning. The proposed filters are designed on high resistive silicon substrate of 500µm and 300 thicknesses. The tunability is achieved by using MEMS based varacter replaced with fix capacitor in conventional combline filter. First, the microstrip combline filter is designed at the centre frequency of 9.5 GHz and then tuning is achieved by varying the capacitance in the designed combline filters. The electromagnetic simulation has been carried out using HFSS v15 software based on finite element method (FEM). The tuning of the filter on silicon substrate of 500 μm is achieved by changing the capacitance value from 0.2035 pF to 0.4035 pF in the model in HFSS, which resulted the tuning in the frequency range of 7.85 to 10.35GHz. Insertion loss of design filter is in the range of 1dB within the tuning range. In case of substrate thickness 300 μm the tuning of the filter is achieved by changing the capacitance value from 0.293 pF to 0.403 pF in the model in HFSS, which resulted the tuning in the frequency range of 8.80 to 9.90 GHz. Insertion loss of design filter is in the range of ∼1.2dB within the tuning range.

Comparison of active and passive EMI filters to reduction conducted noise

The article presents the results of experimental studies of passive and active EMI filters for reduction of conducted noise. Firstly, the article presents selected structures of passive filters that have been tested in terms of insertion loss parameter describing their efficiency. Then, active filters were used to improve the efficiency of insertion loss of passive filters under the same conditions. Finally, the results and conclusions are drawn from the measurements of both types of filters for the reduction of conducted noise.

The high temperature superconducting filters and its application progress

Microwave filters are essential elements in many areas of RF/microwave engineering. The crowded frequency spectrum has put forward higher requirements on channel filters. Not only very high close-to-band rejections are required to prevent interference to or from closely neighboring channels, but also very low insertion loss is required to reduce system noise figure. Some RF/microwave system require in-band group-delay and amplitude flatness to minimize signal degradation even further. Surface resistance of high temperature superconducting (HTS) material is about 1000 times less than the best conventional metals such as copper and silver at microwave frequency. So a significant effort has been put into the research and realization of high performance microwave HTS filters since the discovery of HTS materials. HTS microwave filters with remarkably high performance have been constructed in the past 30 years. For example, by selecting appropriate resonators with high quality factors and employing well-designed coupling structures with week coupling coefficients, some HTS filters can have fractional band width (FBW) blow 0.1% with very high selectivity. The insertion loss of some HTS filters can be as low as 0.05 dB. With above excellent performance, HTS filters can not only eliminate unwanted interference but also minimize noise figure of the microwave system. HTS filters and their front-end subsystems have also been successfully applied to many fields and brought multiple economic returns and social benefit. It is reported that HTS receiver front-end subsystem, which integrate with narrow-band highly selective HTS filters and low noise amplifiers (LNA) in a cryocooler, has been employed in more than 10000 base stations in America. According to the promotion materials, the ultra-low-loss and high sensitivity of the HTS receiver can translate into 10%–15% or more increased base station coverage area and data throughput. In some cases carriers could add 8% or more usable resource blocks and capacity due to the high selectivity of the HTS receiver, valued at hundreds of millions of dollars. Design technology of HTS filters has been developed rapidly at an incredible speed. In recent years, many efforts have concentrated on novel HTS filter design technologies, including those in high power handling capability filters, multiplexer or multiband filters and frequency tunable filters. Some research groups are trying to develop all-HTS integrated microwave front-end receivers, which integrate HTS filter, oscillators, mixers and antenna into a whole chip. The all-HTS integrated front-end receiver could make the system compact, efficient, and be able to exploit the full potential of the superconductive components. In this paper, the research status, trend of development and application progress about HTS filters are reviewed. The best performances of HTS filters ever reached in specifications such as insertion loss, FBW, out of band rejection, skirt slope and in band group delay are firstly reviewed. Then the remarkable progress in the most recent years which stand for the research trends of HTS filter technology is presented in detail. At last the application of HTS filters and their front-end subsystems to mobile communications, space or satellite communication technology, radar detective system, deep space detection and radio astronomy is also reviewed.

Compact Coaxial Filters for BTS Applications

A new class of coaxial cavity filters with low-profile suitable for base transceiver station applications is proposed. The benefits of the technology are volume reduction, high performance, and superior spurious-free response. An equivalent lumped element circuit allows for a fast and efficient initial design of the resonators. Full-wave optimization is required to produce the final configuration of the filters. Experimental results demonstrate the high performance of the proposed filters. The electrical length of the experimental resonators is as low as $\lambda _{0}/16$ . The measured insertion loss of the five-pole filter is 0.92 dB at 722 MHz. Experimental results show a spurious-free response of the order of 7.6 times.

Design of Dual-band Bandpass Filter for GSM 950 MHz and GSM 1850 MHz Applications using Lumped Component

Filter is an electrical circuit that designed to pass the signal generated at certain frequencies and block the signal generated by all other frequencies. Dual-band filter is a filter designed to work on two frequency bands simultaneously. This research aims to design a dual-band bandpass filter for GSM applications, to pass signals on two frequency bands simultaneously, namely GSM900 with 950 MHz center frequency and bandwidth of 25 MHz and GSM1800 with 1850 MHz center frequency and bandwidth of 75 MHz. The steps taken to design a bandpass filter dual-band is starting to make a normalized lowpass filter Butterworth, then transform the lowpass filter into a bandpass filter with a center frequency of 950 MHz and 1850 MHz, then combining the two bandpass filters are to be filter dual-band with center frequency 950 MHz and 1850 MHz, and finally analyze the performance of the dual-band bandpass filter. Performance filter parameters to be analyzed is the return loss (S11), insertion loss (S21) and Voltage Standing Wave Ratio (VSWR). From the analysis and discussion for dual-band bandpass filter is obtained that: center frequency of the filter is at 950 MHz and 1850 MHz. Filter bandwidth at center frequency of 950 MHz is 25 MHz (962.5 MHz - 937.5 MHz) and filter bandwidth at center frequency of 1850 MHz is 75 MHz (1812.5 MHz - 1887.5 MHz). Return loss (S11) filter at frequency of 950 MHz and 1850 MHz < -10 dB. Insertion loss (S21) filter at frequency of 950 MHz and 1850 MHz > -3 dB. VSWR at frequency of 950 MHz and 1850 MHz < 2.

Experimental optimization of concatenated taper Mach–Zehnder interferometers operating in the 1000–1150 nm wavelength range

Experimental optimization of all fiber Mach-Zehnder interferometers based on concatenated tapers is presented. The experimental optimization was realized by the application of the four parameters Taguchi algorithm, and the insertion loss of comb filters operating around the 1064nm wavelength was taken as the parameter to be optimized. The out of band losses were reduced from around 2.5dB (43.7%) to a minimum of 0.45dB (9.84%) in one case, and from 2.9 (48.71%) to 0.4dB (8.79%) by using a fixed tapers pair's geometry with 1 mm×1 mm×1 mm of up-taper length/waist length/down-taper length, respectively, and a waist diameter of 40μm.