Search

In this paper, a new approach for the design of wideband bandpass frequency selective surface (FSS) is proposed based on the microstrip patch resonator and substrate integrated waveguide (SIW) cavity. Originating from the similarity of field distributions between the patch and SIW resonators, the patch resonator is concentrically embedded within the SIW cavity. In this context, resonant modes in both patch resonator and SIW cavity can be generated without enlarging the circuit size. Then, the slotlines are introduced to the ground layer to establish cross‐couplings to produce transmission zeros (TZs) for better out‐of‐band performances. For demonstration, a fourth‐order bandpass FSS is constructed, simulated, and fabricated. The measured results agree with the simulated ones, verifying that the proposed design method possesses attractive advantages of low profile, compact size, high frequency selectively, and nice universality. [ABSTRACT FROM AUTHOR]

A novel multi‐band pass negative group delay circuit has been designed and proposed. The circuit consists of three types of components: capacitance, inductance, and resistance. An n‐order bandpass negative group delay circuit was analyzed and presented, and taking a three‐frequency bandpass negative group delay circuit as an example, the influence of different component values on the circuit group delay and insertion loss was analyzed. The actual test results of this circuit are consistent with the simulation results, and it can achieve the function of a multi‐bandpass circuit. In actual testing, the circuit frequencies with negative group delay are 49, 82, and 102 MHz, with corresponding group delay values of −2.177, −2.058, and −1.903 ns and corresponding insertion loss values of −5.810, −5.835, and −5.866 dB. [ABSTRACT FROM AUTHOR]

In this paper, a compact differential bandpass filter with wide‐stopband is presented. The proposed differential filter is designed using two circular substrate‐integrated waveguide (SIW) cavities coupled through a pair of symmetric coupling slots. The filter operates in TM110 mode of the circular SIW cavity. The degenerate TM110 mode is shifted to higher frequency by the introduction of two pairs of perturbation vias. The center frequency of the differential passband can be tuned by changing different design parameters such as location of perturbation vias and length of the slotlines. As a proof of the proposed concept, a second‐order differential bandpass filter is designed, fabricated, and measured. The measured results are in good agreement with the electromagnetic‐simulated ones. [ABSTRACT FROM AUTHOR]

A new design approach to achieve compact size and high common‐mode (CM) suppression of balanced filters is proposed with two back‐to‐back microstrip semi‐circular patch resonators. In feeding structures, metalized via holes are adopted to vertically feed patches by differential pairs. Then, TM11 mode is excited and TM31 mode can be rejected, resulting in wideband differential‐mode (DM) harmonic rejection. Besides, with a slotline etched in the common ground plane, desired coupling strength can be achieved for a target bandwidth. Meanwhile, by virtue of the stacked structure, source‐load coupling can be easily introduced to generate transmission zeros close to the passband. With theory guidance, two balanced filter prototypes centered at 2.4 GHz are designed. Simulation and measurement results both indicate that proposed balanced filters exhibit high DM and CM performances as well as a compact size about 0.26λg × 0.53λg. [ABSTRACT FROM AUTHOR]

This paper proposes a novel compact tri-band bandpass filter based on two coupled asymmetrical stub-loaded resonators (ASLR). The proposed filter can achieve three resonant frequencies by tuning uniform impedance line, short-circuit stub, and open-circuit stub, respectively. In addition, the asymmetrical stub can be loaded at any position of the main branch, which will facilitate the circuit design for no impedance of special ratio is needed, and the design bound can be alleviated. Meanwhile, thanks to its simple structure, the whole filter occupies an area of 0.021 λg2 based on RO4350B substrate, much smaller than other similar tri-band filters. Measurement results show that the filter achieves fractional bandwidths (FBW) of 7.5%, 6.4% and 4.2%, respectively for three bands. The proposed filter is small and can achieve a high-frequency selectivity at 2.45 GHz, 3.5 GHz and 5.25 GHz, corresponding to Bluetooth, World Interoperability for Microwave Access (WiMAX) and Wireless Local Area Network (WLAN), respectively. The proposed filter will find a wide application in wireless communications thanks to its attractive advantages. [ABSTRACT FROM AUTHOR]

This paper is concerned with a six-element bridged-T RC network, which is a bandstop filter, but by reorientation, can also achieve bandpass characteristics. The general configuration is analyzed for its transfer function and then two special cases are considered. Interestingly, the bandstop configuration in one case and the bandpass configuration in both cases show over-unity gain in a small range of frequencies. [ABSTRACT FROM AUTHOR]

This paper proposes a novel approach to implement an internal standard (IS) correction in single particle inductively coupled plasma mass spectrometry (SP ICP-MS), as exemplified for the characterization of Au nanoparticles (NPs) in complex matrices. This approach is based on the use of the mass spectrometer (quadrupole) in bandpass mode, enhancing the sensitivity for the monitoring of AuNPs while also allowing for the detection of PtNPs in the same measurement run, such that they can serve as an internal standard. The performance of the method developed was proved for three different matrices: pure water, a 5 g L−1 NaCl water solution, and another water solution containing 2.5% (m/v) tetramethylammonium hydroxide (TMAH)/0.1% Triton X-100. It was observed that matrix-effects impacted both the sensitivity of the NPs and their transport efficiencies. To circumvent this problem, two methods were used to determine the TE: the particle size method for sizing and the dynamic mass flow method for the determination of the particle number concentration (PNC). This fact, together with the use of the IS, enabled us to attain accurate results in all cases, both for sizing and for the PNC determination. Additionally, the use of the bandpass mode provides additional flexibility for this characterization, as it is possible to easily tune the sensitivity achieved for each NP type to ensure that their distributions are sufficiently resolved. [ABSTRACT FROM AUTHOR]

This study presents three dual-band lowpass–bandpass filters. The first handles lowpass and bandpass bands through its fifth-order and third-order Chebyshev filter responses, respectively. This filter uses three circuits to achieve flexibility in cutoff frequencies and fractional bandwidths. The second is a higher-order filter: it is a dual-band filter with ninth-order lowpass and fifth-order bandpass responses. In general, an extra 50- $\Omega $ transmission line might be required to connect each port conveniently to an external circuit for the first or second proposed filter, which could increase the circuit area. The third is a dual-band filter with a $\lambda $ /4 impedance transformer near each port to facilitate connections with external circuits. Each of the proposed dual-band lowpass–bandpass filters has a systematic design procedure when the lowpass and bandpass band responses are given separately. In addition, the proposed filters can provide rapid prediction through the use of ideal circuit simulations instead of full-wave simulations.

This paper presents how to design and simulate two different topologies of a bandpass (BP) rectangular waveguide filter using a direct coupled resonator technique operating at 12 GHz. The filters are characterized by a cross coupling (CM) which produces a single attenuation pole at finite frequency used to realize the bandpass response. The filter resonators provide3rd and 4th order designs with a pseudoelliptic response using High Frequency Structure Simulator (HFSS) simulator. Transmission zeros are obtained through coupling between the fundamental mode and high mode. The filter structures are validated leading to obtain transmission zeros close to the bandpass. The simulated waveguide filters with a central frequency exhibit an insertion loss of 0.4/0.3dB and a return loss of 20/23dB for the whole bandwidth ranging from 11.85GHz to 12.15GHz that show good electromagnetic responses for the simulated rectangular waveguide filters.

This paper is a complement to the existing literature on RC networks having over unity gain, where only low-pass and high-pass filters were considered. Here, we consider networks having bandpass characteristics, with over unity gain. These are thoroughly analyzed, simulated, and the important parameters of each are presented in the form of Tables. [ABSTRACT FROM AUTHOR]

A novel concept of balun bandpass reconfigurable active filter is proposed here. The structure is composed of a three-stage balun filter having fractional bandwidth (FBW) of 13% with matched amplifier inserted between the last two stages. This technique of incorporating active device in balun filter gives an advantage of obtaining re-configurability, while compensating for loss at the balanced ports. The modified structure is able to yield re-configurability of frequency, bandwidth, power division ratio (PDR) and wide band stop response along with reduction in size (77 mm × 42 mm). The amplifier is accommodated within the second loop and is not cascaded with the balun filter, thus saving the space. The proposed balun filter has a varying gain of approximately 4–11 dB as bias changes from Ids =52 to Ids =78 mA, while simulating in MWO AWR software. The active balun filter has been fabricated on RT Duroid substrate. The measured results show | S11| < −15 dB from 1.9 to 2.18 GHz, which is comparable with simulation results. The novelty of this work is to obtain bias-dependent frequency, bandwidth and PDR re-configurability with varying gain. [ABSTRACT FROM AUTHOR]

In this paper, a miniaturized ultra‐wideband filter with ultra‐wide stopband and high selectivity using a capacitive loading stub in a multimode structure is proposed. The second, third, and fourth harmonics of the proposed filter are all suppressed on account of using a capacitive loading stub, which makes it have the characteristic of an ultra‐wide stopband. In addition, there are two transmission zeros located at the upper stopband close to the passband, which improves the selectivity of the proposed filter. The proposed filter is fabricated and measured, and the result shows the filter with the center frequency f0 1.185 GHz has 151% 3‐dB fractional bandwidth. Its upper stopband is extended to 9.18 GHz (7.75 f0) and the 20‐dB roll off rate is 212.5 dB/GHz. What's more, the size of the proposed filter is 0.175 λg × 0.18 λg, where λg is the guided wavelength at the center frequency f0. [ABSTRACT FROM AUTHOR]

In this paper, a novel loop based multiband bandpass frequency selective surface (FSS) structure has been presented. The presented unit cell has been designed using the two square loops and two octagon loops for achieving the multiband characteristics which are extensively utilized in wide range of applications. The sporadic arrangement of these four loops is the key factor to pass the Wi-Max (2.5–2.7 GHz, 3.4–3.6 GHz) and WLAN (center frequency 5.5 GHz) frequency bands. The miniaturized structure gives a wide bandwidth at all the three bands and provides stable resonance for a wider angle of incidence, due to the orientation of loops. The size of unit cell is 0.15 λ × 0.15 λ where λ is the wavelength of first resonant frequency. A 16 × 16 array of the proposed unit cell is fabricated over a FR4 substrate and its simulated and measured results are presented which are in good agreement. The advantage of the proposed FSS structure is its miniaturized configuration showing wider angular stability and polarization independent characteristics. [ABSTRACT FROM AUTHOR]

The first Hall network is examined in detail to find and optimize the peak magnitude, which occurs in its bandpass response. It is shown that the same network with a reorientation, can act as a bandstop filter. This is also examined in detail and choice of parameters to maximise the peak/minimize the dip is discussed. In both networks, the critical frequency (of peak/dip) can be controlled by a potentiometer, keeping the magnitude of the peak/dip a constant. [ABSTRACT FROM AUTHOR]

A method of designing bandpass frequency select surface (FSS) has been proposed based on series and parallel equivalent circuit thought in this article. The novel dual‐band equivalent circuits are designed. The equivalent admittances were extracted, and resonance frequency was calculated. The dual‐band properties of circuit were verified, which lays foundation for the designing of FSS structure. The FSS unit designed in this paper adapts single‐layer thin substrate, and it has simple structure, is easy to implement. The thickness of dual‐band is 0.017 wavelength. The angle stability and polarization stability of FSS are improved by utilizing miniaturization ideas and adding symmetrical structures. The dual‐band FSS consists of two inner and outer loops nested. The inner ring is the Jerusalem structure, and the outer ring is folded structure, both can be independently adjustable resonance frequency. It can realize stable resonance at center frequencies under oblique incidence of 0° to 60° for both TE and TM polarization. For verifying filtering properties of FSS units, the prototypes are fabricated and measured. The results calculated by full‐wave, equivalent circuit method (ECM) and measurement are in good agreement. [ABSTRACT FROM AUTHOR]

This paper proposes a reconfigurable bandpass filter with a wide tunable range, which is achieved by connecting two tunable passbands with switching diodes. A pair of transmission zeros (TZs) are introduced through the cross‐coupling structure to improve the passband selectivity of the filter, and one more transmission zero is added by the interdigital coupling line to enhance the out‐of‐band suppression and broaden the upper stopband. The simulation and experimental results show that the designed filter with an absolute bandwidth of 100 MHz realizes a tunable frequency band covering 1.5–3 GHz, corresponding to a fractional tunable range of 66.7%. The dimension of the fabricated filter is 0.32 λg × 0.34 λg. [ABSTRACT FROM AUTHOR]

This paper proposes a new method to increase the quality factor of the shadow bandpass filter. The proposed circuit topology is simple, with the use of conventional biquad cell along with external amplifiers. The major advantageous feature is that the quality factor of the filter is boosted up whereas the gain of the external amplifier is significantly reduced. Moreover, the presented idea can be applied to the shadow filter in both current and voltage modes. The proposed scheme is justified via circuit performance. The performance is compared with the previous research works in the same arena. The results show that a feedback signal and a properly chosen gain incredibly boost up the quality factor of the shadow bandpass filter. Simulations by PSpice using 0.18- μ m CMOS-level parameters confirm the validity of the proposed work. [ABSTRACT FROM AUTHOR]

In this brief, a wideband bandpass filter with extremely wide spurious-free stopband and high selectivity is presented. The filter consists of a wideband bandpass cell cascaded with sharp-rejection wide-stopband low-pass filters (WSLPFs), both designed using a mix of lumped and distributed elements. The proposed wideband bandpass cell, consisting of two series LC resonators and shunt-connected open-ended microstrip stubs, produces a three-pole passband with two transmission zeros on its opposite sides. The LC resonators provide suppression of spurious transmission peaks arising due to the main stub, which is further enhanced by the auxiliary stubs in the wideband cell and the WSLPFs. The design technique imbibes the effects of the self-resonating frequencies of the lumped components, and thus enable the filter to achieve the stopband extension irrespective of their size and make. A prototype of the proposed filter, designed at 1.25 GHz with 62.4% bandwidth, shows the stopband extended up to 18.6 times the center frequency with minimum rejection of 19 dB. The selectivity factor of the passband, defined as the 3-dB to 30-dB bandwidth ratio, is 0.65. The maximum filter dimension is less than a quarter of the wavelength at the center frequency, providing a miniature design. [ABSTRACT FROM AUTHOR]

This paper proposes a novel approach to implement an internal standard (IS) correction in single particle inductively coupled plasma mass spectrometry (SP ICP-MS), as exemplified for the characterization of Au nanoparticles (NPs) in complex matrices. This approach is based on the use of the mass spectrometer (quadrupole) in bandpass mode, enhancing the sensitivity for the monitoring of AuNPs while also allowing for the detection of PtNPs in the same measurement run, such that they can serve as an internal standard. The performance of the method developed was proved for three different matrices: pure water, a 5 g L−1 NaCl water solution, and another water solution containing 2.5% (m/v) tetramethylammonium hydroxide (TMAH)/0.1% Triton X-100. It was observed that matrix-effects impacted both the sensitivity of the NPs and their transport efficiencies. To circumvent this problem, two methods were used to determine the TE: the particle size method for sizing and the dynamic mass flow method for the determination of the particle number concentration (PNC). This fact, together with the use of the IS, enabled us to attain accurate results in all cases, both for sizing and for the PNC determination. Additionally, the use of the bandpass mode provides additional flexibility for this characterization, as it is possible to easily tune the sensitivity achieved for each NP type to ensure that their distributions are sufficiently resolved.

Gap waveguide (GW) technology, taking advantage of contactless electromagnetic band-gap (EBG) structures, solves the contact issue of conventional rectangular waveguides and provides a reliable method for packaging with planar circuits. Herein, a slow wave GW (SW-GW) structure with bandpass filtering functionality is presented. Utilizing the low-frequency cutoff characteristic of the GW and band-stop effect of the quasi-periodic transverse corrugations inside the GW, the lower and upper stopbands of the SW-GW can be easily achieved and reconfigured for different bandwidth requirements. The relationship between the dispersion diagram and the filtering characteristics, including the pass and stop bandwidths and group delay (GD), is studied to provide a simple but effective design guideline. The presented SW-GW reduces the design and implementation difficulties of conventional filters, especially wideband filters. A prototype operating at 24–30 GHz is designed and manufactured to validate the idea, and a good agreement is achieved between the measurement and simulation results. [ABSTRACT FROM AUTHOR]

This paper presents how to design and simulate two different topologies of a bandpass (BP) rectangular waveguide filter using a direct coupled resonator technique operating at 12 GHz. The filters are characterized by a cross coupling (CM) which produces a single attenuation pole at finite frequency used to realize the bandpass response. The filter resonators provide3rd and 4th order designs with a pseudoelliptic response using High Frequency Structure Simulator (HFSS) simulator. Transmission zeros are obtained through coupling between the fundamental mode and high mode. The filter structures are validated leading to obtain transmission zeros close to the bandpass. The simulated waveguide filters with a central frequency exhibit an insertion loss of 0.4/0.3dB and a return loss of 20/23dB for the whole bandwidth ranging from 11.85GHz to 12.15GHz that show good electromagnetic responses for the simulated rectangular waveguide filters. [ABSTRACT FROM AUTHOR]

Based on an interlaced grid arrangement, a dual-band dual-polarized bandpass frequency selective structure (FSS) with a large band ratio (BR) is proposed in this letter. The FSS is assembled from vertical layers arranged along x- and y-directions, and the vertical layers arranged along the two orthogonal directions are polarization independent. The grating structures printed on the vertical layers form a higher frequency passband, and by having additional wire-grid polarizers with a high-pass response, a lower frequency passband is formed. The proposed interlaced grid FSS is a combination of two square grid FSSs. Since the distance between adjacent vertical layers is smaller than that of the square grid FSS, the proposed FSS has a wider bandstop response to achieve the design of a large BR. The measured results show that for both TE and TM polarizations, the center frequencies of the two passbands are 2.5 GHz and 15.5 GHz, respectively, with a corresponding BR of 6.2. [ABSTRACT FROM AUTHOR]

In this article, a CMOS tunable channel-selection (CH-SEL) low-noise amplifier (LNA) with a feedforward (FF) $N$ -path filter and a gain- and phase-calibrated interference- cancellation technique is proposed for advanced front-end module (FEM)-less cellular transceivers. The proposed LNA exhibits a high- $Q$ RF bandpass/band-rejection filter characteristic based on a four-path filter, an active blocker cancellation with an FF translational loop, and an LC tank at the input, internal node, and output, respectively. The proposed gain- and phase-calibration block and tunable high-pass filter in the FF filtering path adjust the notch frequency corresponding to the transmitter leakage signal and help realize sharp notch filtering. The proposed CH-SEL LNA with CMOS duplexers compensates for the limited filtering performance of the CMOS duplexer and improves the blocker-tolerance and linearity of the receiver, and thus, can replace surface acoustic wave duplexers in the FEM. Fabricated in the 65-nm CMOS process, the CH-SEL LNA achieves a maximum voltage gain of 19.3 dB, minimum NF of 5.1 dB, and notch rejection ratio of more than 27.8 dB. It can also cover mid-band frequencies in the range of 1.35–2.7 GHz for 5G new radio cellular applications, exhibits an average current of 20 mA from a supply voltage of 1 V, and has an active die area of 1.16 mm2. [ABSTRACT FROM AUTHOR]

The paper presents a novel design of tunable third-order parallel-coupled line filter. The design is based on using short-circuited resonators loaded in series by varactor diodes. Integrating the varactor diodes in the middle of the resonator has made this design unique. It is shown that varying the internal capacitance the varactor diodes has a direct impact on tuning the odd-mode resonance frequency of the resonator. The proposed concept is validated by comparing theoretical equations to circuit simulations. Very good agreement is found. When the concept is applied to the design of a third-order parallel line-coupled filter, the obtained tuning range is ±27.3% (central frequency tuned between 1.74 and 3.05 GHz). In addition, the filter presents good electrical performance and compact size (73% surface miniaturization) with respect to the state of art results. [ABSTRACT FROM AUTHOR]

This paper presents a pathological voice identification system employing signal processing techniques through cochlear implant models. The fundamentals of the biological process for speech perception are investigated to develop this technique. Two cochlear implant models are considered in this work: one uses a conventional bank of bandpass filters, and the other one uses a bank of optimized gammatone filters. The critical center frequencies of those filters are selected to mimic the human cochlear vibration patterns caused by audio signals. The proposed system processes the speech samples and applies a CNN for final pathological voice identification. The results show that the two proposed models adopting bandpass and gammatone filterbanks can discriminate the pathological voices from healthy ones, resulting in F1 scores of 77.6% and 78.7%, respectively, with speech samples. The obtained results of this work are also compared with those of other related published works. [ABSTRACT FROM AUTHOR]

Non-shaping dynamic element matching (DEM) randomization schemes are widely adopted for wideband Nyquist-rate digital-to-analog converters (DACs) within transmitter architectures. Here, randomization translates the mismatch-induced distortion into white noise from dc to $\text{F}_{\mathrm{ s}}$ /2 range. However, the DAC performance for various bands within the Nyquist range cannot be improved using non-shaped DEMs as their inherent structure cannot be made programmable. Conversely, mismatch-shaping DEMs can be made tunable to shape the DAC errors over various signal bands, which makes them suitable for wireless transmitter applications. This paper presents the design methodology for high-order mismatch-shaping DEM architectures suitable for wideband Nyquist DACs. The challenge in designing high-order DEM structures for Nyquist DACs is to make them programmable to cover various signal bands within the Nyquist range and to operate them at high-frequencies demanded by the applications. Moreover, the stability of the high-order loop-filter within the DEM and its implementation cost is of great concern. This work details techniques to design programmable, stable, and hardware efficient high-order DEM structures for wideband Nyquist DACs. The DEM structures are implemented on an UltraScale+ FPGA device for prototyping and validation. Furthermore, the DEM design operation is validated by obtaining the measurement results interfacing with a 5-bit analog DAC.

In this article, a novel wideband bandpass power divider (PD) with out-of-band multi-transmission zeros (TZs) is presented. It consists of $2M$ shunted short-circuited stubs (SCSs), ($M + N$) cascaded coupled line sections, and ($M + N - K_{N}$) isolation resistors. There are two types of topologies, and the number of TZs is solely determined by $N$. Through even- and odd-mode analyses, general simultaneous equations for characteristic impedances, coupling strengths, and isolation resistors are derived with the proposed algorithm. By suitably selecting all the design parameters, all the $S$ -parameters ($S_{11}$ , $S_{21} = S_{31}$ , $S_{22} = S_{33}$ , and $S_{32}$) of the proposed topology could provide an equal-ripple response with controllable ripple level in the passband. For a given fractional bandwidth (FBW), TZs and out-of-band rejection level can be designed independently. For further optimization, several isolation resistors can be omitted with the unchanged performances. For verification, two experimental circuits are fabricated and measured. Good agreement between the measured and simulated results is attained so as to successfully validate the correctness of the proposed design approach. [ABSTRACT FROM AUTHOR]

Lumped-element grids provide an attractive option for wave propagation control in electromagnetic compatibility (EMC) engineering. This article investigates the peak shielding effectiveness (SE) of a diode grid used for protection of enclosures with apertures against high-intensity radiation fields (HIRFs). The nonlinearly loaded aperture is investigated with an efficient hybrid field-circuit simulation approach. Numerical experiments show that design aspects, e.g., aperture and enclosure size, grid density, impedance characteristic of lumped loads, play an important role in the field transmission through a diode grid which is nonlinear and time-variant. With a physics-based analysis of the interaction between the grid and the enclosure-backed aperture, nonlinear shielding techniques are identified that allow a control of the peak SE between 0 and 26 dB in novel ways. For the first time, the peak SE curve of a diode grid is demonstrated with four different field intensity dependencies, i.e., intensity low-pass, intensity high-pass, intensity bandpass, and intensity band-stop selectivities from tens V/m to hundreds of V/m. By considering design aspects into a two-step optimization procedure, practical guidelines are provided for the nonlinear shielding implementation. [ABSTRACT FROM AUTHOR]

A continuous-Time delta–sigma modulator (CT-DSM) excels at high-bandwidth (BW), high-dynamic-range analog-to-digital conversion. However, CT-DSMs suffer from PVT variation, high sensitivity to timing errors, and are restricted in sampling rate. This work proposes a hybrid-loop (HL) DSM architecture to mitigate the disadvantages of CT-DSM while providing similar performance. This work also introduces a bandpass time-interleaved noise-shaping (TINS) successive-approximation (SAR) architecture, which increases the sampling rate of TINS SAR. A prototype HL-DSM with bandpass TINS-SAR quantizer is built in 28-nm CMOS and occupies a die area of 0.09 mm2. The measured peak SNDR is 67.5 dB for a 100-MHz BW. The total power consumption is 13.4 mW at a sampling rate of 1.6 GS/s. The resulting Schreier FoM of 166.2 dB is comparable to state-of-the-art CT-DSM converters. [ABSTRACT FROM AUTHOR]

In this paper, a novel design of frequency-selective surface (FSS) based on coupled stubs-loaded ring resonators (SLRRs) is proposed. The proposed FSS exhibits quasi-elliptic bandpass filtering characteristic at C-band. And each unit cell of the structure is composed of two SLRRs coupled by a circular aperture. A novel method of transmission line (TL) model is proposed to investigate the operating principle of a single SLRR under normal incidence plane wave. Moreover, the operating mechanism of the proposed FSS is further researched with the aid of the equivalent circuit model (ECM) analysis method. Due to the symmetric and low-profile physical structure, the FSS keeps stable frequency response under oblique incident plane wave for both transverse electric (TE) and transverse magnetic (TM) polarizations. Finally, the designed FSS is fabricated and measured. The measured results agree well with the simulated results. The measured results indicate that the proposed FSS exhibits a dual-polarized and stable bandpass frequency response with two transmission zeros (TZs) at around 5.71 and 6.87 GHz under different incident angles up to 40°.

This work presents a novel microstrip dual-band bandpass filter (BPF) using meandros spirals and patch cells, which is proposed for the first time by this work. It occupies a very compact size of 0.0017 λg2. The proposed filter is designed to operate at Fo1=0.85 GHz and Fo2=1.85 GHz for GSM-850/GSM-1900 applications. In addition to the small size, it has several advantages in terms of wide fractional bandwidths (FBW), low insertion losses and high return losses at both channels. The simulated insertion losses at the lower and upper passbands are 0.05 dB and 0.1 dB, respectively. Another advantage of the proposed BPF of this work is the attenuated harmonics, where it is able to suppress 1st, 2nd, 3rd and 4th harmonics (4.11 Fo1) with -20 dB maximum harmonic level.

Signal processing is critical to a myriad of biological phenomena (natural and engineered) that involve gene regulation. Biological signal processing can be achieved by way of allosteric transcription factors. In canonical regulatory systems (e.g., the lactose repressor), an INPUT signal results in the induction of a given transcription factor and objectively switches gene expression from an OFF state to an ON state. In such biological systems, to revert the gene expression back to the OFF state requires the aggressive dilution of the input signal, which can take 1 or more d to achieve in a typical biotic system. In this study, we present a class of engineered allosteric transcription factors capable of processing two-signal INPUTS, such that a sequence of INPUTS can rapidly transition gene expression between alternating OFF and ON states. Here, we present two fundamental biological signal processing filters, BANDPASS and BANDSTOP, that are regulated by D-fucose and isopropyl-ß-D-1-thiogalactopyranoside. BANDPASS signal processing filters facilitate OFF-ON-OFF gene regulation. Whereas, BANDSTOP filters facilitate the antithetical gene regulation, ON-OFF-ON. Engineered signal processing filters can be directed to seven orthogonal promoters via adaptive modular DNA binding design. This collection of signal processing filters can be used in collaboration with our established transcriptional programming structure. Kinetic studies show that our collection of signal processing filters can switch between states of gene expression within a few minutes with minimal metabolic burden--representing a paradigm shift in general gene regulation. [ABSTRACT FROM AUTHOR]

We propose a self-biased inverter-based amplifier for realizing a high-speed low-power second-order single-loop continuous-time bandpass delta-sigma modulator (CT-BP-ΔΣM). The design is amenable to nanoscale CMOS and exploits a single self-biased pseudo-differential inverter with a positive feedback to replace conventional op-amps used in an integrator configuration. The modulator also uses a 5-bit asynchronous successive approximation register (ASAR) quantizer. With a 30 MHz bandwidth at 400 MS/s sampling rate and 100 MHz intermediate frequency (IF), the modulator achieves 61 dB dynamic range (DR) and 58 dB SNDR while consuming 2.5 mW from a 1V supply. The core area in 28 nm LP CMOS is 0.04 mm2. A 38.6 fJ/conv.-step figure of merit is achieved. [ABSTRACT FROM AUTHOR]

In this article, a novel compact microstrip dual-narrowband bandpass filter (DNBPF) is presented with wide and high rejection levels in the stopbands. The location of each passband is independently controllable/tunable/selectable. The filter structure is made up of three-coupled-asymmetrical transmission lines, open-ended stubs and direct-transmission lines. Employing these lines can generate two narrowband passband filters. By combining these passband filters, the proposed DNBPF is configured. The proposed DNBPF is investigated. The center frequency of the first and second passband are 5.745 and 6.489 GHz, respectively. Also, the proposed DNBPF presents the fractional 3-dB bandwidth of the first and second passband 3.66 and 2.33%, respectively. It has the flattest group delay variations in comparison with previously published papers due to the design freedom. |S12|< -30 dB is from 10.1 to 19.25 GHz in the last stopband. The occupied area of the proposed DNBPF is 0.225 λ g × 0.11 λ g , where λ g is the guided wavelength at the first center frequency. [ABSTRACT FROM AUTHOR]

This letter presents a non‐reciprocal diplexer with integrated functions of a conventional bandpass diplexer and two isolators. This is achieved by spatio‐temporally modulating the resonator frequencies in a coupled‐resonator diplexer. Due to the high channel‐to‐channel isolation, the diplexer channels can be independently modulated without affecting each other. A microstrip diplexer example is demonstrated with good agreement between the measurement and the simulation. The fabricated diplexer has two non‐reciprocal bandpass channels at 829 and 997 MHz, with a minimal insertion loss of 4.9 and 6.1 dB, and a 20‐dB isolation bandwidth of 38 and 37 MHz, respectively. To the best of the authors' knowledge, this is the first time that a non‐reciprocal diplexer has been presented. [ABSTRACT FROM AUTHOR]

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

In this letter, a dual-polarized 3-D frequency selective surface (3-D FSS) based on square metallic waveguides (SMWs) is proposed, which produces a flat passband with two transmission zeros in a relatively wide rejection. Because all resonances occur along propagation direction without complex resonators, a small unit cell size and simple geometry is achieved, resulting in good angular stability and easy implementation. By an equivalent circuit model, its operating principle is explained. At last, the measured results of an implemented FSS show that a stable response under the incident angles up to 60° for dual polarizations is realized. [ABSTRACT FROM AUTHOR]

This paper studies a fuze radome system applied to millimeter waves. The system consists of feed antenna, radome, planar FSS array or curve conformal array. Microstrip antenna is used as the feed antenna. Based on the principle of equispaced and equal period respectively, cross units loading single layer dielectric form planar and curve FSS array. The FSS radome system can improve the permeability of hood to electromagnetic waves (EM) of passband, and reduce the interference of complex EM in the external environment to the system. The FSS radome will not deteriorate radiation characteristics of the feed antenna. The planar FSS radome has a passband of 98.2 GHz to 101.55 GHz with -10dB relative bandwidth of 3.35%. The curve FSS radome has a passband of 96.3 GHz to 101.8 GHz with -10dB relative bandwidth of 5.5%. In addition, the radiation characteristics of the proposed system are analyzed. It is found that the radiation pattern of the antenna is basically consistency before and after loading the radome. [ABSTRACT FROM AUTHOR]

In this paper, a compact dual‐band bandpass filter (DB‐BPF) is implemented by using a pair of coupled stepped impedance resonators (SIRs) and a pair of λ/2 bended resonators for the modern wireless communication systems such as WiMAX and WLAN (3.4 and 5.4‐GHz). The physical layout is presented and explained the establishment of an LC equivalent circuit. Moreover, the second passband of the proposed dual‐band bandpass filter can be independently controlled by inserting the open‐circuited stubs at the end of the λ/2 bended resonators without increasing the circuit size. Simulation results show that the second passband can be ranged from 5.6 to 4.8‐GHz with the bandwidth of 400 ± 96‐MHz, whereas the first passband is fixed with the bandwidth of 280 ± 8.5‐MHz. The measured results exhibit the insertion losses (S21) lower than 1.2 and 1.4 dB, and the return losses (S11) of −23 and −32 dB at the first and second passbands, respectively, which show a good agreement with simulation results. The dual‐band microstrip filter is fabricated on RT/Rogers 4003 substrate with a compact size of 0.24λg × 0.25λg. [ABSTRACT FROM AUTHOR]

This paper presents a new design of a super compact Ultra wideband (UWB) band-pass filter (BPF) with rejection of X-band satellite applications. For covering the UWB bandpass, the proposed filter is realized using hybrid technique which is achieved by using a Microstrip-Coplanar waveguide-Microstrip transition. The basic structure consists of a modified microstrip in the top layer and CPW in the bottom layer. Later, open-circuited stubs are embedded in the top to implement in-band transmission zeros (TZ) so as to circumvent interference. The simulated results show that the UWB bandpass filter has a high adaptation (S11 ≤ −18 dB) and insertion loss better than 0.4 dB at the passband. The impedance bandwidths are about 114% (3–11 GHz) with upper stopband extends to more than 14 GHz with a depth of greater than 38 dB. In addition, the UWB BPF shows a flat group delay performance with a variation of about 0.15 ns over the entire bandwidth. A prototype of the filter is fabricated and tested. Good agreement is achieved between measurement and simulation. The proposed UWB BPF is compact in size with overall dimensions of 14 by 9.2 mm2. Consequently, the obtained results prove that the presented filter is suitable for UWB wireless devices.

This paper presents a wideband bandpass filter design based on a short‐circuited circular patch resonator with inductively loaded slots. The cavity model method is used to analyze the excited resonances of the resonator. According to the illustration of the cavity model, the TM010 mode is excited as the fundamental mode, the resonant frequency of which is much lower than that of the TM110 mode and can be further lowered by the loaded arc‐oriented slots. Therefore, the proposed resonator can be used to design a filter with compact size. In addition, one of the two orthogonal degenerate TM110 modes can be independently tuned by the slot along the symmetric plane without affecting the TM010 mode. Since the resonant frequency of each mode can be tuned independently by the parameters of the slots, and the coupling between resonant modes of the resonator and source/load can be adjusted by the feeding angle and the capacitive loaded stubs on the feeding lines, the center frequencies and bandwidths of the designed bandpass filters can be tuned easily. The analysis is theoretically and experimentally verified by two examples with good agreement between the simulated and measured results. [ABSTRACT FROM AUTHOR]