Bandstop Notch Research Articles

Dual band Orthogonal Polarized 2-port MIMO Antenna for Cognitive Radio Applications

An arrangement of orthogonally aligned antennas over two planes of a substrate is designed in this paper. The design is a novel miniaturized cognitive model operating at LTE, C-band and X-band with sufficient band stop notch. The antenna is etched over a 0.8 mm thick FR-4 Epoxy substrate of dimension 15 mm x 15 mm. On one side the antenna is a hexagonal slotted microstrip antenna and on the other side is a partial CPW type hexagonal patch antenna. The top hexagonal patch antenna is a wide band from 1800 MHz to 12000 MHz. With the use of a slot on the patch creates one notch from 2240 MHz to 5090 MHz and another notch is created at 6200 MHz to 8100 MHz. Thus, the working bands comprise of LTE 1900, Wi-Fi 5G and X-band under a single polarization. Similarly, the second antenna has its first resonance at LTE 1900 and the second resonance at X-band with a polarization orthogonal to the antenna at top. Being a miniaturized antenna, the cognitive radio provides gain ranging from 2.0 dB at lower frequency to 5.4 dB at higher frequency. The isolation over the operating bands suggests non-interference between the antennas.

Design of Stray Radiation Sensor for ITER ECE Diagnostic

The Electron Cyclotron Emission (ECE) diagnostic has a primary role in the measurement of electron temperature profile and electron temperature fluctuations in ITER. This diagnostic shall be exposed to significant power due to unabsorbed Electron Cyclotron Heating (ECH) power in the plasma. The expected stray power loads could be a few tens of watts, and therefore, the protection of millimetre wave components is one of the design challenges of ITER ECE diagnostic. This protection system includes sensors, a band stop notch filter, and a shutter to stop the RF stray radiation from being incident on the sensitive components. The sensors will be positioned along the ECE transmission line, and shall be used for real-time power monitoring of the stray radiation. Here, we describe a novel design of a sensor for monitoring the stray radiation power. This sensor is a Schottky Diode rectenna, known for high-power and high-speed millimetre wave detection capability. It consists of a 2x2 microstrip patch antenna array, a matching circuit, a diode, and a low pass filter. The antenna array is designed analytically and optimized in CST Microwave Studio, for wide reception angle, high gain, and low side lobe levels. Furthermore, the rectifying circuit is optimized using Agilent Advanced Design System (ADS) software to get better rectification and impedance matching of the signal, thereby improving its detection sensitivity. The ADS simulation results show that the detection sensitivity is about 1000V/W for input power of -30 dBm at 170 GHz, thereby achieving the required performance of the sensor.

Differential‐to‐single‐ended crossover based on dumbbell‐shaped defected ground resonators for dual‐band applications

This article presents a novel differential-to-single-ended (DS) crossover by using two rings included of controllable frequency ratio of composite right- and left-handed (CRLH) transmission lines for dual-band applications. To reject the out-of-band differential-mode transmission coefficient, two dumbbell-shaped defected ground resonators (DGRs) are utilized over the differential transmission lines. Theoretical analysis proves that the frequency ratio can be controlled by choosing the number of designing CRLH cells and the parameter values appropriately. Also, desired electrical lengths and impedances of DGRs were obtained at the bandstop notch of differential-mode transmission coefficient by conducting common- and differential-mode analysis of lumped element equivalent circuit. To validate the proposed structure, two fabricated prototypes including the DS crossover designing at 1.8 and 4.2 GHz and separate differential lines with embedded DGRs were fabricated and measured. Measurement mixed-mode results exhibit that the fabricated crossover has great results at both frequency bands and has a good out-of-band differential insertion loss rejection.

Design of Surface Defects Loaded Selectively Notched W-Band Waveguide Filter for Millimeter Wave Diagnostic in Fusion Reactor

In the fusion experiment, sensitive radio frequency signal diagnostic instruments need to be protected against high power stray radiation coming from the Electron Cyclotron Resonance Heating. The design of a stopband notch filter in the transmission path of the diagnostic system is helpful to avoid the stray radiations. This work presents the study and design methodology of the notch filter based on a circular corrugated waveguide Bragg reflector that provides a single stopband between 75 and 105 GHz. The existence of the HE11 mode, i.e. the only propagating mode in the W-band notch filter is the key aspect in the design of the filter. The proposed notch filter is compact and spans only 46.62 cm in length with an inner diameter of 16.4 mm. By optimizing the number of corrugation to 140, their period to λ through parametric analysis and unconventionally introducing uniformly spaced surface defects within the filter structure, a single stopband at 90 GHz is obtained corresponding to the LP12 Bragg resonance. The notch filter may be useful in wideband diagnostics like Electron Cyclotron Emission and reflectometry in the fusion plasma experiments.

A concurrent dual-band CMOS low noise amplifier at 2.4/5.2 GHz for WLAN applications

<span>This paper presents a concurrent dual-band CMOS low noise amplifier (LNA) at operating frequency of 2.4 GHz and 5.2 GHz for WLAN applications. The proposed LNA employed cascode common source to obtain high gain using 0.13-µm CMOS technology. The concurrent dual-band frequencies are matched using LC network band-pass and band-stop notch filter at the input and output stages. The filters help to shape the frequency response of the proposed LNA. The simulation results indicate that the LNA achieves a forward gain of 21.8 dB and 14.22 dB, input return loss of -18 dB and -14 dB at 2.4 GHz and 5.2 GHz, respectively. The noise figure of 4.1 dB and 3.5 dB with the input third-order intercept points 7 dBm and 10 dBm are obtained at 2.4 GHz and 5.2 GHz, respectively. The LNA dissipates 2.4 mW power at 1.2 V supply voltage with a chip size of 1.69 mm2.</span>

Performance improvements of a tunable bandpass microwave photonic filter based on a notch ring resonator using phase modulation with dual optical carriers.

A tunable bandpass microwave photonic filter can be achieved by using a notch ring resonator with optical phase modulation. However, the filter's out of band rejection ratio and shape factor are limited due to the ring resonator's residual phase, which can seriously degrade the filter's performance. By using dual optical carriers and setting their wavelengths oppositely detuned from two resonant frequencies of a notch ring resonator, the residual phase induced by the ring resonator at radio frequencies falling outside the region of the notch stopband is reduced, thus the out-of-band rejection ratio and shape factor of the microwave photonic filter are greatly improved. The proposed microwave photonic filter was both verified theoretically and experimentally. Compared with single optical carrier method, the out-of-band rejection ratio of the filter can be enhanced from 17.7dB to 31.5dB, and the filter's shape factor is improved from 3.05 to 1.78. Besides, the filter's frequency and bandwidth can be tuned by varying the wavelengths of the two optical carriers and the ring resonator's coupling coefficients. Finally, a tunable bandpass microwave photonic filter with frequency tuning range of 2~14GHz, 3dB bandwidth tuning range of 0.673~2.798GHz is demonstrated.

Notched UWB filter using exponential tapered impedance line stub loaded microstrip resonator

In this study, two ultra-wideband (UWB) filters having the fractional bandwidth >120% are designed, analysed and fabricated. The first filter is designed with three quarter-wavelength short-circuited stubs and second by using exponential tapered impedance line stub loaded microstrip resonator. The first filter consists of five transmission poles within the passband. The second filter with tapered inductive loading on quarter-wavelength high impedance line exhibits a sharp notch stopband around 5.5 GHz, to suppress the interference from IEEE 302.11a WLAN band signals with an attenuation level >30 dB. A good agreement between the measured and predicted results is achieved, which validate the authors’ filter designs.

A $K\text{-}/Ka$ -Band Concurrent Dual-Band Single-Ended Input to Differential Output Low-Noise Amplifier Employing a Novel Transformer Feedback Dual-Band Load

A concurrent dual-band single-ended input to differential output (single-ended-to-differential) low-noise amplifier (LNA) employing a novel transformer feedback single-ended-to-differential dual-band load is proposed. The developed LNA topology is flexible in controlling the stopband notch frequency by optimizing the transformer’s self-inductance and coupling coefficient. It also has a unique advantage in controlling both the stopband rejection and passband gain balance, simultaneously. The LNA is designed using a 0.18- $\mu \text{m}$ BiCMOS process and exhibits the same single-ended-to-differential peak gains of 19.2 dB at 21.5 and 36 GHz in the low- and high-passband, respectively, with the stopband rejection ratio of 37.1 dB. In the single-ended input to single-ended output (single-ended) mode operation, the designed LNA exhibits the measured peak gains of 15.7/16.6 dB at 21.5 GHz and 15.7/16.7 dB at 36 GHz for the two signal paths. It achieves the best measured single-ended noise figures of 4.3/4.0 and 4.3/4.2 dB for the two signal paths in the respective low and high passbands. The LNA also attains the measured differential gain and phase imbalances of 0.9/1.0 dB and 0.5/10.4 degree in the low/high passband, respectively. This LNA is the first concurrent dual-band single-ended-to-differential LNA integrated on-chip operating in ${K}$ - and Ka -band.

Tunable Single-Passband Microwave Photonic Filter Based on Integrated Optical Double Notch Filter

A novel-integration-based technique employing a cascaded pair of microring resonators on silicon-on-insulator platform that can achieve a tunable single-passband microwave photonic filter with improved shape factor and extinction ratio is presented. It is based on an integrated optical double notch filter using a cascaded pair of nonidentical microring resonators, in conjunction with optical phase modulation. This results in minimal net phase being introduced by the overall filter at radio frequencies falling outside the region of the notch stopband, thus enabling nearly full antiphase cancellation of the modulation sidebands, which results in the achievement of an improved filter shape factor and extinction ratio. Additionally, it features a bandwidth that is directly determined by the difference between the bandwidths of the two optical notch filters, rather than by their absolute individual bandwidths. Experimental results have verified the concept, and have demonstrated a single-passband filter having tuning range of 6–17 GHz, a shape factor of 1.78, shape-invariant tuning, and a good out-of-band suppression ratio of approximately 20 dB throughout the entire tuning range.

A Novel Hammer-Shaped UWB Antenna with Triple Notched-Band for Rejecting RLS, WLAN and XSCS bands

A novel hammer-shaped UWB printed antenna with triple notched stop bands is presented and fabricated on FR-4 substrate with size of 40×40×1.6 mm3. The proposed antenna is composed of hammer-shaped patch with C-shaped slot, U-shaped slot on feed line, and inverted stepped notch and bevel edges with pair of L-shaped slots in partial ground plane. The fabricated antenna is tested and obtained impedance bandwidth 2.89 ̶ 11.6 GHz with three notched stop bands 3.15 ̶ 3.7 GHz, 5.45 ̶ 6.8 GHz, and 7.5 ̶ 8.8 GHz, for radiolocation system (RLS), wireless local area networks (WLAN), and X-band satellite communication system (XSCS) bands, respectively. Moreover, the antenna result shows omnidirectional radiation pattern, average gain of 3.10 dBi over the whole UWB band except at the notched frequency bands.

Control of Magnon-Photon Coupling Strength in a Planar Resonator/Yttrium-Iron-Garnet Thin-Film Configuration

A systematic study of the coupling at room temperature between ferromagnetic resonance and a planar resonator is presented. The chosen magnetic material is a ferrimagnetic insulator (yttrium iron garnet, YIG) which is positioned on top of a stop band (notch) filter based on a stub line capacitively coupled to a 50 Ω microstrip line resonating at 4.731 GHz. Control of the magnon-photon coupling strength is discussed in terms of the microwave excitation configuration and the YIG thickness from 0.2 to 41 μm. From the latter dependence, we extract a single spin-photon coupling of g 0 /2π = 162 ± 6 mHz and a maximum of an effective coupling of 290 MHz.

English

This paper proposes a design of an extremely wideband printed monopole antenna with dual notched stop bands for worldwide interoperability for microwave access (WiMAX) and wireless local area networks (WLAN). The individual notch frequencies are controlled by the individual split ring resonators (SRRs) and central notch frequency is determined by the individual SRRs physical dimensions. Predicted extremely wide impedance bandwidth of antenna is 2.67-22 GHz, for VSWR 2 is achieved for rejecting WiMAX (3.3-3.69 GHz) and WLAN (5.15-5.825 GHz) band signals. Significant gain reduction over the notched stop bands and nearly omnidirectional radiation patterns over operating frequencies is also analysed.

Compact printed ultra-wideband antenna with two notched stop bands for WiMAX and WLAN

Compact printed ultra-wideband antenna with two notched stop bands for WiMAX and WLAN

Planar ultra‐wideband antenna with five notched stop bands

A printed ultra-wideband (UWB) antenna with five notched stop bands is presented. By introducing a pair of arc-shaped slots, two defected ground structures and an open-loop resonator, five sharp notches are achieved at frequencies of 2.4, 3.2, 5.2, 5.8 and 7.5 GHz. The proposed antenna has been fabricated and tested. The measured results indicate that the proposed design not only supports UWB bandwidth requirements but rejects five narrow bands to avoid possible interference with existing communication systems. In addition, the proposed antenna has relatively omnidirectional radiation patterns in passbands.

ANALYSIS OF A SMALL UWB FILTER WITH NOTCH AND IMPROVED STOPBAND

A microstrip based Ultra-Wideband (UWB) Bandpass Filter (BPF) with a notch at WLAN and simultaneously improved stopband till 18GHz is proposed. Meander shaped Defected Ground Structures (DGS) are used to implement the notch within the passband and two double U-shaped DGS structures present under the input and output feeding lines are used to attain the suppressed stopband. An equivalent circuit model of the proposed UWB fllter structure is presented in the manuscript. Experimental results are in good agreement with the simulated data.

All‐optical reconfigurable microwave photonic signal processor

AbstractAn all‐optical reconfigurable high resolution microwave photonic signal processor is presented. It is based on a 2 × 1 electro‐optic modulator and an active‐fiber Bragg‐grating‐pair filter. Experimental results demonstrate a sharp bandpass filter response and a narrow stopband notch filter response which can be obtained by controlling the optical sources. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1989–1991, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23557

Elliptic-type bandpass filter and bandstop notch filter inspired by metamaterial NRI-TL topology

Compact and highly selective filters can be implemented by loading a transmission line with series printed capacitors and shunt resonant λ/4 stubs resembling the familiar printed negative-refractive-index transmission-line topology. Simulation and experimental results of a microstrip two-stage bandpass filter and a bandstop notch filter are presented. The four-pole bandpass filter exhibits an elliptic-type response with 3% fractional bandwidth. The microstrip bandstop notch filter exhibits a 50 dB deep stopband and a notch Q of 50. Both filters were designed at an operating frequency of 2.0 GHz.

Nickel nanowires for planer microwave circuit applications and characterization

The dynamic properties of uniform one-dimensional arrays of high aspect ratio nickel nanowires have been studied by ferromagnetic resonance (FMR) technique at 24GHz. The fundamental magnetic parameters such as spontaneous magnetization, gyromagnetic ratio (γ), and magnetic anisotropies of the nanowires are derived from the angular variation of resonance field Hr(θH) positions. The effective fields of the nanowire system were observed to decrease with increasing length of the nanowires. Further, the use of nanowires as a tunable stop-band notch filter in a coplanar waveguide geometry has been assessed. The stop-band frequency (fr) is observed to be tunable up to 14GHz with an applied field (H) of up to 4kOe. The kink in the fr(H) data gives the measure of the effective field (Heff) of the nanowire system. The theoretical fitting of fr(H) data to resonance relation yields values of Heff and γ which are a little higher than the conventional FMR results.

Multistage high-order microring-resonator add-drop filters

We propose and demonstrate a multistage design for microphotonic add-drop filters that provides reduced drop-port loss and relaxed tolerances for achieving high in-band extinction. As a result, the first microring-resonator filters with a rectangular notch stopband in the through port (to our knowledge) are shown, with extinctions exceeding 50 dB. Reaching 30 dB beyond previous results, without postfabrication trimming, such extinction levels open the door to microphotonic notch circuits for spectroscopy, wavelength conversion, and quantum cryptography applications. Combined with a low-loss, high-index-contrast electromagnetic design in SiN and frequency-matched microring resonators, this approach led to the first demonstration of flattop microphotonic filters meeting the stringent criteria for high-spectral-efficiency integrated add-drop multiplexers. The 40 GHz wide filters show a 20 nm free spectral range, 2 dB drop loss, and suppression of adjacent channels by over 30 dB.