Adam Reda Hasan Alhawari

X-band miniaturized wideband bandpass filter utilizing multilayered microstrip hairpin resonator

This paper presents a new design of miniaturized wideband bandpass fllter using microstrip hairpin in multilayer conflguration for X-band application. The strong coupling required for wideband fllter is realized by arranging flve hairpin resonators in two layers on difierent dielectric substrates. Since adjacent resonator lines are placed at difierent levels, there are two possible ways to change coupling strength by varying the overlapping gap between two resonators; vertically and horizontally. In this paper, simulated and measured result for a wideband fllter of 4.4GHz bandwidth at 10.2GHz center frequency with flfth order Chebyshev response is proposed. The fllter is fabricated on 0.254mm thickness R/T Duroid 6010 and R/T Duroid 5880 with dielectric constant 10.2 and 2.2 respectively using standard photolithography technique. Two fllter conflgurations based on vertical (Type 1) and horizontal (Type 2) coupling variation to optimize the coupling strength are presented and compared. Both conflgurations produce very small and compact fllter size, at 5:0 £ 14:6mm 2 and 3:2 £ 16:1mm 2 for the flrst and second proposed fllter type respectively. The measured passband insertion losses for both fllters are less than 2.3dB and the passband return loss is better than i16dB for fllter Type 1 and i13dB for fllter Type 2. Very small and compact fllter is achieved where measured results show good agreement with the simulated responses.

An aligned-gap and centered-gap rectangular multiple split ring resonator for dielectric sensing applications

This paper presents the design and development of a planar Aligned-Gap and Centered-Gap Rectangular Multiple Split Ring Resonator (SRR) for microwave sensors that operates at a resonance frequency around 5 GHz. The sensor consists of a microstrip transmission line loaded with two elements of rectangular SRR on both sides. The proposed metamaterial sensors were designed and fabricated on Rogers RT5880 substrate having dielectric constant of 2.2 and thickness of 0.787 mm. The final dimension of the proposed sensor was measured at 35 × 14 mm2. Measured results show good agreement with simulated ones as well as exhibiting high Q-factor for use in sensing application. A remarkably shift of resonance frequency is observed upon introduction of several sample with different dielectric value.

Miniaturized Ultra-Wideband Antenna Using Microstrip Negative Index Metamaterial

Abstract A three left-handed metamaterial unit cell antenna is presented in this article for ultra-wideband applications. Each left-handed metamaterial unit cell is a combination of a modified octagonal split-ring resonator, an octagonal spiral resonator, a capacitance-loaded strip, and a wire in order to achieve a design that simultaneously exhibits both negative electrical permittivity and negative magnetic permeability, which promises an extraordinary index of negative refraction to enhance the radiated power of the antenna, consequently improving the antenna system. The antenna design was etched on an FR4 epoxy substrate (Farnell Electronic Components Limited, Selangor D.E., Malaysia) with an evident compact size of 25 × 25 × 1.6 mm 3 . Return loss measurements demonstrated that this antenna achieves 94% bandwidth for a voltage standing wave ratio less than 2 over the frequency band of 5.2–13.9 GHz, with a maximum gain and directivity of 3.85 dBi and 5.45 dB, respectively, at 10.5 GHz. These measurement results show good agreement with those of the simulations as well as good omni-directional characteristics within its operating frequency band. The proposed metamaterial antenna is compact and highly directive and has a tunable operational frequency especially for ultra-wideband applications.

Compact narrowband bandpass filter using dual-mode octagonal meandered loop resonator For WiMax application

In this paper, a new design of a compact narrowband bandpass fllter is proposed. This new narrowband bandpass fllter is designed using an octagonal form of dual-mode closed-loop microstrip ring resonator based on a meander structure in order to achieve compactness. The designed fllter has a 3dB fractional bandwidth (FBW) of 5% at 2.3GHz. The fllter has been fabricated on Taconic CER-10 substrate having 0.64mm thickness and a relative dielectric constant of 10. Experimental results show good agreement with simulated values. Apart from WiMax, this new model of fllter is also useful for WLAN and mobile communication applications, since it is compact in size, low loss, and low cost with good performance of elliptic response with sharp rejection and adequate fractional bandwidth.

Compact Microstrip Bandpass Filter with Sharp Passband Skirts Using Square Spiral Resonators and Embedded-Resonators

The aim of this paper is to produce and develop a new four-pole microstrip bandpass filter (BPF) structure for high selectivity applications. The microstrip BPF is designed using Chebychev lowpass prototype with passband ripple of 0.05 dB and bandwidth of 120 MHz, which operates at center frequency of 2.3 GHz. This filter is designed by using square spiral resonator structures and embedded-resonator topology with the same fundamental frequency to make it more compact; furthermore, it has high quality performance in terms of the frequency responses. The size of the compact microstrip filter is 24.74 × 21.20 mm2. The proposed filter was designed, fabricated and tested. The measured results show that the minimum passband insertion loss is 2.65 dB, while the measured return loss is better than –11 dB in the passband. Very good agreement between the simulated and measured results was observed.

ANTIPODAL VIVALDI ANTENNA PERFORMANCE BOOSTER EXPLOITING SNUG-IN NEGATIVE INDEX METAMATERIAL

Despite its popularity, the conventional Vivaldi antenna has long sufiered from some design problems, such as tilted beam, low or inconsistent directivity and gain, complicated design and fabrication methods, and limited size reduction. These setbacks make its progress lag on the fast track of technological demand. Thus, the antenna overall performance is anticipated to improve by incorporating negative index metamaterial (NIM) into the design method, plus, it is also tunable. In this study, the design uses linearly-tapered shape-loading structure, as its projected performance crucially depends on the space in between the antenna arms, a prerequisite to further boost its performance when combined with NIM technology. A unique slitting approach synchronizes the integration between the Vivaldi antenna and NIM where a single layer NIM piece is simply snugged into the slit perpendicular to the middle antenna substrate. The major improvement in the spotlight is the capability of NIM to focus the entire beam so that it can radiate to the targeted direction. The measurement results are similar to the simulations in terms of high gain, where the gain and directivity of the antenna are increased up to 4dB. The contrast of overall performance between the plain modifled Vivaldi antenna and the ones with NIM evidently asserts the expected contribution of snug and boost method applied and attests its signiflcant potentials for a broad range of ultra-wideband applications.

A miniature fractal-based dual-mode dual-band microstrip bandpass filter design

In this paper, a fractal-based complementary split-ring resonator (CSRR) has been introduced as a defected ground structure (DGS) in the ground plane of a dual-mode microstrip bandpass filter to produce a new compact filter with dual-band response. The conventional double square ring resonator structure is modified such that its inner ring is made with a fractal shape instead of a square. Measured and simulation results show that the resulting filter offers a dual passband response; the higher passband is attributed to the dual-mode microstrip ring structure, whereas the lower passband is as a result of the embedded CSRR DGS structure. In addition, the results show that the position of the lower passband could be varied, to a certain extent, without affecting the position of the higher passband by applying higher fractal iteration levels to the inner split ring. These features, together with the compact size the proposed filter offers, make it suitable for use in a wide variety of dual-band communication applications. Measured results, carried out on filter prototypes, have been found in agreement with those theoretically predicted.

Miniaturized Metal Mount Minkowski Fractal RFID Tag Antenna with Complementary Split Ring Resonator

This paper proposes miniature radio frequency identiflca- tion (RFID) tag antenna designed to operate on metallic objects, in the UHF frequency range (915MHz), without signiflcantly degrading its read range. The antenna structure is composed of two parts: Part 1 comprises two square patches electrically connected to the ground plane through vias while Part 2 is an unconnected inter-layer con- sisting of two square complementary split ring resonators to allow for capacitive reactance increase. Consequently, its self-resonant frequency will shift towards low frequency, which theoretically allows shrinking RFID tag antenna into smaller size. The antenna was simulated and measured to verify its conjugate matching with chip impedance. The results of experimental tests show that the proposed RFID tag ofiers a maximum read range of 0.82m when placed on a metallic object. The tags overall size is 36:7£18:1£3:165mm 3 . Both simulation and measurement results are provided to validate the design.

Compact Wideband Bandpass Filter Using Single Corners-Cut Isosceles Triangular Patch Resonator

Compact and simple bandpass fllter (BPF) structure using microstrip isosceles triangular patch resonator (ITPR) is proposed. The new fllter design technique is based on two main ideas: Firstly, cutting the corners of the triangular structure, to make the fllter size more compact. Secondly, etching slit in staircase form near the base of the triangle, in order to improve the fllter performances. The proposed fllter was designed and fabricated on Taconic CER-10 substrate with a relative dielectric constant of 10 and a thickness of 0.64mm using standard photolithography process. The flnal dimension of the proposed fllter is measured at 5.7mm £ 7.6mm. Measured S- parameters showed that the fllter achieves a 3-dB fractional bandwidth of 55% at center frequency of 10.36GHz, with measured insertion loss of 2.08dB and measured return loss better than 10dB. The measured results are in good agreement with the simulated results.

Gain Enhancement of a Microstrip Patch Antenna Using a Reflecting Layer

A low profile, unidirectional, dual layer, and narrow bandwidth microstrip patch antenna is designed to resonate at 2.45 GHz. The proposed antenna is suitable for specific applications, such as security and military systems, which require a narrow bandwidth and a small antenna size. This work is mainly focused on increasing the gain as well as reducing the size of the unidirectional patch antenna. The proposed antenna is simulated and measured. According to the simulated and measured results, it is shown that the unidirectional antenna has a higher gain and a higher front to back ratio (F/B) than the bidirectional one. This is achieved by using a second flame retardant layer (FR-4), coated with an annealed copper of 0.035 mm at both sides, with an air gap of 0.04 as a reflector. A gain of 5.2 dB with directivity of 7.6 dBi, F/B of 9.5 dB, and −18 dB return losses () are achieved through the use of a dual substrate layer of FR-4 with a relative permittivity of 4.3 and a thickness of 1.6 mm. The proposed dual layer microstrip patch antenna has an impedance bandwidth of 2% and the designed antenna shows very low complexity during fabrication.