Методы подавления шумов и помех в электронных системах. (Noise reduction techniques in electronic systems)

The ultrawideband (UWB) planar antenna is designed as a circular metallic patch fed by a coplanar waveguide (CPW). This antenna provides the impedance bandwidth of the wideband response from 2.5 to 12 GHz. To achieve the notched characteristics at desirable frequencies, the electric ring resonator (ERR) incorporated into the CPW feedline is proposed for use in the planar configuration of the UWB antenna. The notched frequency band is controlled by dimensions of the ERR structure. The single-notched band can be obtained by placing a single ERR beneath the CPW structure. For implementation of the multinotch band, a modified multimode structure of the ERR is examined. Reconfigurability of the first notched band is provided by using a digital variable capacitor (DVC) instead of ERR's quasi-lumped capacitance. The results of simulations and measurements are in a good agreement.

Ultrawideband (UWB) Planar Antenna with Single-, Dual-, and Triple-Band Notched Characteristic Based on Electric Ring Resonator

The explosive progress of electronic devices and communication systems results in the production of undesirable electromagnetic pollution, known as electromagnetic interference. The accumulation of electromagnetic radiation in space results in the malfunction of commercial and military electronic appliances, and it may have a negative impact on human health. Thus, the shielding of undesirable electromagnetic interference has become a serious concern of the modern society, and has been a very perspective field of research and development. This paper provides detailed insight into current trends in the advancement of various polymer-based materials with the effects of electromagnetic interference shielding. First, the theoretical aspects of shielding are outlined. Then, the comprehensive description of the structure, morphology and functionalization of the intrinsic conductive polymers, polymers filled with the different types of inorganic and organic fillers, as well as multifunctional polymer architectures are provided with respect to their conductive, dielectric, magnetic and shielding characteristics.

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Progress in polymers and polymer composites used as efficient materials for EMI shielding

A very small coplanar waveguide (CPW)-fed rectangular slot antenna with dual band-notched characteristics for super ultrawideband (UWB) applications is proposed. This antenna consists of a rectangular slot, a beveled rectangular patch, two S-shaped slits cut in the ground plane and an elliptical ring slot (ERS) etched in the patch. The corners of a simple rectangular patch are beveled to improve the impedance bandwidth, especially at the middle frequencies of the band. In addition, a pair of semicircle slots is etched in the ground plane to enhance the bandwidth to more than 23 GHz. A pair of S-shaped slits connected to the rectangular slot, and an ERS cut in the beveled rectangular patch, is employed to create band-notched performances in WiMAX and WLAN spectrum, respectively. The proposed antenna has a very small size of $15 \times 15 \text{mm}^{2}$ , and therefore, it is one of the smallest UWB slot antennas that have been reported until now, and provide a very wide impedance bandwidth from 2.6 to more than 23 GHz for $\text{VSWR} with dual band-notched properties.

Very Small Dual Band-Notched Rectangular Slot Antenna With Enhanced Impedance Bandwidth

Graphene RF and microwave passive components such as coplanar waveguide transmission lines, open/short-circuited resonators and wideband antenna on paper substrate were designed, screen printed and characterized in this work. The experimental results demonstrate that the screen printed graphene passive components can be used for RF signal transmitting, processing and radiating/receiving; revealing that graphene ink can be a low cost alternative to much more expensive metal nanoparticle inks, such as silver nanoparticle ink. The screen printed graphene is processed at low temperature so that it is compatible with heat-sensitive flexible materials like papers, PTFE (Polytetrafluoroethylene) and textiles. The screen printed graphene passive components reported here are of high conductivity, high flexibility, light weight and low cost, making them ideal candidate for low cost wearable electronics. This work makes it prospective to manufacture RF and microwave passive components in mass production by screen printing in much lower cost to any other known techniques.

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Graphene radio frequency and microwave passive components for low cost wearable electronics

A printed compact coplanar waveguide fed triangular slot antenna for ultra wide band (UWB) communication systems is presented. The antenna comprises of a triangular slot loaded ground plane with a T shaped strip radiator to enhance the bandwidth and radiation. This compact antenna has a dimension of 26 mm × 26 mm when printed on a substrate of dielectric constant 4.4 and thickness 1.6 mm. Design equations are implemented and validated for different substrates. The pulse distortion is insignificant and is verified by the measured antenna performance with high signal fidelity and virtually steady group delay. The simulation and experiment reveal that the proposed antenna exhibits good impedance match, stable radiation patterns and constant gain and group delay over the entire operating band.

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A compact CPW fed slot antenna for ultra wide band applications

A compact ultra wide band (UWB) antenna with dual band notch characteristics is proposed. The antenna consists of a coplanar waveguide (CPW) fed bevelled rectangular patch and a modifled rectangular ground plane. A Z-shaped meander line parasitic element and a pair of symmetrical L-shaped quarter-wavelength stubs are employed to realise band-notched functions at WiMAX and WLAN bands respectively. By optimizing the dimensions and positions of these notch structures, the desired notch-bands of WLAN and WiMAX are achieved. Unlike other dual band-notched antennas reported in literature this antenna has a merit of regulating the centre frequency as well as the bandwidth of both the notched bands easily and independently. The measured i10dB S11 covers the bandwidth from 2.5 to 11.5GHz, with two notched bands from 3.3 to 3.6GHz and 5.2 to 5.75GHz. The proposed antenna exhibits nearly omni-directional radiation patterns with moderate gain and small group delay variations less than 0.5ns over the entire operating bandwidth except at the notched bands. Moreover, by using antenna transfer function, the time domain characteristic of the antenna is also studied to conflrm its suitability for UWB pulse communication.

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Analysis of CPW-Fed UWB Antenna for WiMAX and WLAN Band Rejection

A material sample of Camphour Sulphonic Acid doped Polyaniline (PANI-CSA) is contemplated towards its conceivable use as a microwave shield. Shielding towards electromagnetic interferences (EMI) is measured over various frequency bands by the waveguide method. Plane wave electromagnetic theory is used to generalize the overall reflection and transmission coefficients of the polymer. EMI shielding of the polymer, in the form of Shielding Efficiency (SE), is analyzed over the microwave frequency range from 2 to 18 GHz, demonstrating the potential value of the polymer as an electromagnetic interference (EMI) shield for commercial purposes. The shielding film is fabricated using standard procedure with CSA as the dopant and m-cresol as the solvent. The shielding effectiveness as high as 45 dB for the sample of PANI doped with CSA is observed.

Electromagnetic Interference Shielding Efficiency Enhancement of the PANI-CSA Films at Broad Band Frequencies

In this paper we discuss two types of band pass filters at millimeter wave frequency for different permittivity conditions in thick-film dielectric. Both edge coupled and end coupled band pass filters are designed at 90GHz for 8 and 9 permittivity values. The filters have a fractional band width of 0.1 and having an insertion loss below 3dB and rejection more than 18dB. The thick-film dielectric loss is comparatively less for such high frequency range for our designs. The cost and the fabrication complexity are much less since it uses the thick-film process.

Parallel and end coupled microstrip band pass filters at W-band

A detailed study on the performance of a high impedance surface on lossy dielectric is presented in this paper. It is observed that the structure, which is an array of square loops on a grounded dielectric, behaves as artificial magnetic condutor, narrowband absorber or perfect electric conductor depending on the dielectric loss. An equivalent circuit modelling is used to theoretically explain how this transition is happening. The observed narrowband absorption (bandwidth = 0.08GHz) of the thin (0.016λ) lossy dielectric is scalable to different operating frequencies by varying the structure parameters. The simulation studies on the effect of structural and dielectric properties on the characteristics of this HIS are also dealt with in this paper. Experimental investigation is in good agreement with simulated result and equivalent circuit modelling.

Arimpoorpallan Ouseph Lindo

Papers

A compact CPW fed slot antenna for ultra wide band applications

Analysis of CPW-Fed UWB Antenna for WiMAX and WLAN Band Rejection

Electromagnetic Interference Shielding Efficiency Enhancement of the PANI-CSA Films at Broad Band Frequencies

Parallel and end coupled microstrip band pass filters at W-band

Radar Cross Section Reduction Property of High Impedance Surface on a Lossy Dielectric