Yaqeen S. Mezaal

New Microstrip Bandpass Filter Designs Based on Stepped Impedance Hilbert Fractal Resonators

ABSTRACT The proposed microstrip bandpass filters in this paper have compact sizes and narrow band responses which are the requirements of modern wireless communication circuits. These filters are constructed from dual-edge coupled resonators; each resonator is based on applying step impedance resonator generator on first and second iteration of Hilbert fractal resonators on each segment of each iteration level. They have been designed for the industrial, scientific, and medical band (ISM) band applications at a centre frequency of 2.4 GHz using a substrate with a dielectric coefficient of 9.6 and thickness of 0.508 mm. The performance of bandpass filters has been analysed using a method of moments (MoM) based on software package, Microwave Office 2009, from Advanced Wave Research Inc., which is widely adopted in microwave research and industry. Simulation responses show that these filters possess good frequency response characteristics with second harmonics suppression. Moreover, these filters showed noticeable miniaturization which is an important feature for many communication applications. The simulated and measured results are in good agreement.

Miniaturised microstrip bandpass filters based on Moore fractal geometry

This paper presents new microstrip bandpass filter design topologies that consist of dual edge-coupled resonators constructed in the form of Moore fractal geometries of second and third iteration levels. The space-filling property for proposed fractal filters has found to produce reduced size shapes in accordance with sequential iteration levels. These filters have been prepared for ISM band applications at a centre frequency of 2.4 GHz using a substrate with a dielectric coefficient of 10.8, dielectric thickness of 1.27 mm and metallisation thickness of 35 µm. The output responses of each fractal bandpass filter have been determined by a full-wave-based electromagnetic simulator Sonnet software package. Simulated and experimental results are approximately compatible with each other. These responses clarify that these fractal filters have good transmission and return loss characteristics with blocked higher harmonics in out-of-band regions.

A new design of dual band microstrip bandpass filter based on Peano fractal geometry: Design and simulation results

The proposed filter design topology is based on dual coupled resonators constructed in the form of Peano fractal geometry. A dual-band microstrip bandpass filter with a quasi-elliptic response has been designed for first time based on 1st iteration Peano fractal geometry at resonant frequencies of 2.25 GHz and 4.825 GHz using a substrate of a relative dielectric constant of 10.8 and thickness of 1.27 mm. The performance of the bandpass filter structure has been analyzed using a method of moments (MoM) based software package, Microwave Office 2009, from Advanced Wave Research Inc. Results show that this filter possesses good frequency response characteristics in addition to dual bands gained which can be used for modern communication applications.

New Dual Band Dual-Mode Microstrip Patch Bandpass Filter Designs Based on Sierpinski Fractal Geometry

Dual band dual mode chebychev micro strip band pass filter designs are introduced for first time in this paper. The proposed filter designs are based on the use of dual mode square slotted patch micro strip resonator. These filter structures are fractally generated using Sierpinski fractal curve geometry applied to the conventional square micro strip patch from 1st to 2nd iteration levels where the first band designed at fundamental frequencies (5.475, 5.45 and 5.4) GHz for each iteration while the second band( 8.925, 9.15, 9.05) GHz for each iteration. These filters have been designed using a substrate with a dielectric constant of 10.8 and thickness of 1.27mm. The performance of filter structures, based on resonators has been evaluated using a full-wave based electromagnetic simulator Sonnet software package. Performance simulation results show that these filter structures are compact in addition to good frequency responses and narrow bands gained.

Wide Bandpass and Narrow Bandstop Microstrip Filters based on Hilbert fractal geometry: design and simulation results.

This paper presents new Wide Bandpass Filter (WBPF) and Narrow Bandstop Filter (NBSF) incorporating two microstrip resonators, each resonator is based on 2nd iteration of Hilbert fractal geometry. The type of filter as pass or reject band has been adjusted by coupling gap parameter (d) between Hilbert resonators using a substrate with a dielectric constant of 10.8 and a thickness of 1.27 mm. Numerical simulation results as well as a parametric study of d parameter on filter type and frequency responses are presented and studied. WBPF has designed at resonant frequencies of 2 and 2.2 GHz with a bandwidth of 0.52 GHz, −28 dB return loss and −0.125 dB insertion loss while NBSF has designed for electrical specifications of 2.37 GHz center frequency, 20 MHz rejection bandwidth, −0.1873 dB return loss and 13.746 dB insertion loss. The proposed technique offers a new alternative to construct low-cost high-performance filter devices, suitable for a wide range of wireless communication systems.

A Novel Design of Two Loosely Coupled Bandpass Filters Based on Hilbert-zz Resonator with Higher Harmonic Suppression

New characteristics of fractal design scheme has been introduced to generate compact two poles capacitively coupled micro strip band pass filter by using additional coupling stubs for different wireless applications. The presented fractal scheme is based on specific type of Hilbert space-filling curve which is called Hilbert-zz fractal geometry. The performance of generated band pass filter structure has been analyzed using Sonnet software package with a relative dielectric constant of 9 and a substrate thickness of 1.27 mm. Results show that these filters possess good transmission and return loss characteristics, besides higher harmonics suppressions, meeting the specifications of most of wireless communication systems.

Investigation of Dual-Mode Microstrip Bandpass Filter Based on SIR Technique

In this paper, a new bandpass filter design has been presented using simple topology of stepped impedance square loop resonator. The proposed bandpass filter has been simulated and fabricated using a substrate with an insulation constant of 10.8, thickness of 1.27mm and loss tangent of 0.0023 at center frequency of 5.8 GHz. The simulation results have been evaluated using Sonnet simulator that is extensively adopted in microwave analysis and implementation. The output frequency results demonstrated that the proposed filter has high-quality frequency responses in addition to isolated second harmonic frequency. Besides, this filter has very small surface area and perceptible narrow band response features that represent the conditions of recent wireless communication systems. Various filter specifications have been compared with different magnitudes of perturbation element dimension. Furthermore, phase scattering response and current intensity distribution of the proposed filter have been discussed. The simulated and experimental results are well-matched. Lastly, the features of the proposed filter have been compared with other designed microstrip filters in the literature.

Investigation of New Microstrip Bandpass Filter Based on Patch Resonator with Geometrical Fractal Slot.

A compact dual-mode microstrip bandpass filter using geometrical slot is presented in this paper. The adopted geometrical slot is based on first iteration of Cantor square fractal curve. This filter has the benefits of possessing narrower and sharper frequency responses as compared to microstrip filters that use single mode resonators and traditional dual-mode square patch resonators. The filter has been modeled and demonstrated by Microwave Office EM simulator designed at a resonant frequency of 2 GHz using a substrate of εr = 10.8 and thickness of h = 1.27 mm. The output simulated results of the proposed filter exhibit 22 dB return loss, 0.1678 dB insertion loss and 12 MHz bandwidth in the passband region. In addition to the narrow band gained, miniaturization properties as well as weakened spurious frequency responses and blocked second harmonic frequency in out of band regions have been acquired. Filter parameters including insertion loss, return loss, bandwidth, coupling coefficient and external quality factor have been compared with different values of perturbation dimension (d). Also, a full comparative study of this filter as compared with traditional square patch filter has been considered.

New microstrip semi-fractal antenna: Design and simulation results

New microstrip antenna derived from the first iteration of Sierpinski fractal portions has been designed in this study as semi-fractal structure. This antenna has been designed using single layer substrate and dual via ports to operate with resonant frequencies at 2.55, 3.02 and 7.08 GHz within 2 to 8 GHz frequency range. The proposed antenna has miniature dimensions with good radiation performances, which can be integrated in many wireless devices.

OTP encryption enhancement based on logical operations

With continuous development of hacking technologies, it is necessary to provide users with a protected background that secures their resources against unlawful access by enforcing control mechanisms. To neutralize such these threats, the enhanced one time pad (OTP) technique has been introduced. Accordingly, to encrypt text, the key is combined with the message. The key length has to have a same length of the message. In this paper, a new method to enhance OTP data encryption using AND and XOR functions has been adopted. Firstly, message and original key are combined by logical AND operation, then the new text will be XORed with a key again to produce more complicated cipher.