Hussein Shaman

New S-Band Bandpass Filter (BPF) With Wideband Passband for Wireless Communication Systems

In this letter, a new wideband bandpass filter (BPF) using microstrip parallel-coupled line structure for s-band applications is proposed. The filter is constructed of two sections of three coupled lines separated by a nonuniform line resonator. In order to introduce one transmission zero at each edge of the desired passband, one of the outer coupled lines of each section is shorted to the ground. The nonuniform resonator is constructed by attaching pair of capacitive open-ended stubs at its central location. This resonator is implemented to increase the filter degree by moving the resonant mode inside the desired passband. The transmission zeros can be located at any desired frequency and the desired bandwidth can be obtained where the bandwidth is reversely proportional to the gap between the coupled lines. The filter is designed to have a wideband passband to cover the whole s-band frequency range. The design is successfully realized and verified by full-wave electromagnetic simulation and the experiment. Excellent agreement between the expected and measured results is obtained.

Novel Design of Ultrabroadband Radar Cross Section Reduction Surfaces Using Artificial Magnetic Conductors

A novel technique for designing ultrabroadband radar cross section (RCS) reduction surfaces using artificial magnetic conductors (AMCs) is proposed in this paper. This technique overcomes the fundamental limitation of the conventional checkerboard design where the reflection phase difference of (180±37)° is required to achieve 10-dB RCS reduction. Initially, a planar surface for broadband RCS reduction is designed with two properly selected AMCs in a blended checkerboard architecture. A 10-dB RCS reduction is observed for more than 83% of the bandwidth (3.9–9.45 GHz) with this blended checkerboard design. After modifying the blended checkerboard design using the proposed novel technique, the 10-dB RCS reduction bandwidth increased to 91% fractional bandwidth (3.75–10 GHz) as the criteria of (180 ± 37)° reflection phase difference is no longer required. Measured data show an excellent agreement between the predicted, simulated, and measured data. Bistatic performance of the surface at various frequencies is also presented. Key steps for designing ultrabroadband RCS reduction checkerboard surface are summarized.

Hairpin microstrip bandpass filter for millimeter-wave applications

A compact microstrip bandpass filter is proposed in this paper for millimeter-wave applications. The filter consists of three new non-uniform coupled-line modified hairpin resonators. The filter is designed to exhibit a fractional bandwidth of about 5.0 % at a center of frequency of approximately 34 GHz. The shapes of the hairpin resonators are modified to suppress the unwanted spurious harmonic response. As a result, the filter exhibits very wide stopband with a rejection level better than 10-dB. In addition, the filter shows a transmission zero close to upper edge of the desired passband which enhances the selectivity of the passband. The filter design is successfully realized on a RT/Duroid 6002 with a dielectric constant of 2.94 and a thickness of 127μm. The filter is simulated, and fabricated to demonstrate the proposed technique where excellent agreement is obtained.

Compact Microstrip Bandpass Filter for Radars and Wireless Communication

Abstract In this article, a new compact microstrip bandpass Alter with ultra-wideband passband is implemented and proposed. The filter is constructed of only one-stage parallel-coupled line and two symmetric short-circuited stubs which are quarter wavelength long at the center frequency. The short-circuited stubs are connected at the input/output ends of the parallel-coupled lines to improve the selectivity at both edges of the desired passband. The design of the proposed filter is successfully realized in theory and verified by full-wave electromagnetic simulation and the experiment. An excellent agreement between the expected and measured results is obtained.

Wearable Flexible Reconfigurable Antenna Integrated With Artificial Magnetic Conductor

This letter presents a wearable flexible reconfigurable folded slot antenna. The antenna is composed of a folded slot and a stub where the reconfigurability is achieved by turning a p-i-n diode on and off, which alters the radiation characteristics of the stub. The operating frequency and polarization of the slot and stub are different. Hence, a polarization-dependent dual-band artificial magnetic conductor (AMC) surface is integrated with the antenna to improve its radiation performance and to reduce the specific absorption rate (SAR). The antenna is designed and fabricated on a flexible substrate, and its performance is measured for both flat and curved configurations. The measurements show an excellent agreement with the simulations. To examine its performance as a wearable antenna, it is measured on a human body. Simulations show that the SAR level is reduced when the AMC surface is used as an isolator. The proposed wearable antenna structure can be used for wireless body area network (WBAN) and Worldwide Interoperability for Microwave Access (WiMAX) body-worn wireless devices.

Compact Ultra-wideband (UWB) bandpass filter with wideband harmonic suppression

A compact microstrip bandpass filter with Ultra-wideband passband is presented in this paper. The filter is designed based on a transmission line bandpass filter with three short-circuited stubs separated by two non-redundant unit elements. Each of the uniform non-redundant unit elements is replaced by a lowpass filter to shrink the physical size of the filter and to reject the second unwanted spurious harmonic of the passband. The filter is successfully designed and the design is verified by full-wave EM-simulation and the experiment. Excellent agreement between theoretical, EM-simulated, and measured results is attained. The filter exhibits a good performance with very low insertion loss of less than 0.6 dB at the mid-band frequency.

Ultra-wideband (UWB) Bandpass Filter with Cascaded Lowpass Filter on Multilayer Liquid-Crystal Polymer (LCP) Substrate

ABSTRACT An ultra-wideband (UWB) bandpass filter with extended upper-stopband on multilayer liquid-crystal-polymer (LCP) substrate is presented in this paper. The proposed filter is designed to select the frequency band from 1.0 to 20 GHz. The filter consists of two parallel-coupled stub-loaded resonators separated by a composite lowpass filter. The composite lowpass filter is implemented to obtain a very wide rejection band. The proposed filter is fabricated using multilayer LCP technology. Excellent agreement between expected and measured results of the filter is obtained. The measurement results show that the fabricated filter has a fractional bandwidth of 180% and a very low insertion loss of less than 0.6 dB at center frequency of 10.5 GHz. The measured filter has a wide stopband and an excellent rejection level higher than 40 dB.

Millimeter-wave microstrip diplexer using elliptical open-loop ring resonators for next generation 5G wireless applications

Design of millimeter-wave microstrip diplexer using elliptical open-loop ring resonators (OLRRs) for the next fifth generation (5G) wireless applications, is presented in this paper. The proposed design consists of two 14-GHz and 28-GHz band pass filters (BPFs). Each BPF consists of elliptical OLRRs that couple two microstrip lines. The geometrical parameters of both BPFs can easily adjust the passband and stopband frequencies to the desired frequencies. The proposed elliptical-shaped OLRRs show good broadband characteristics. The longer OLRR is responsible for achieving passband at the lower resonant frequency of 14-GHz while the shorter OLRR is used to generate a 28-GHz resonant frequency. The proposed diplexer has good return losses and insertion losses at the two resonant frequencies of 14-GHz and 28-GHz.

S-band wideband bandpass filter (BPF) with improved upper-stopband performance for satellite communication systems

A wideband bandpass filter (BPF) using microstrip parallel-coupled line structure for s-band applications is presented in this paper. The filter is constructed of two sections of three coupled lines separated by stub-loaded resonator. The stub-loaded resonator is formed by attaching three open-ended stubs with the two high-impedance microstrip lines in center. The middle open-ended stub is implemented to move the second resonant mode inside the desired passband. The other symmetrical open-ended stubs are introduced to suppress the second harmonic. One of the outer coupled lines of each section is shorted to the ground in order to introduce a finite transmission zero at each edge of the desired passband. Those transmission zeros can be located at any desired frequency. The filter is designed to have a wideband passband to cover the whole s-band frequency range with improved upper-stopband performance.

Design of a compact C-band microstrip bandpass filter for satellite communications applications

A novel and compact microstrip wideband bandpass filter is proposed in this paper for C-band applications. The filter consists of only one section of three parallel-coupled lines which is a quarter wavelength long at the midband frequency. In addition, a quarter wavelength short-circuited stub is added at each end of the central line. As a result, the filter exhibits two new symmetric transmission zeros around the passband which increases the selectivity of both edges of the passband significantly. The transmission zeros can be located at any desired frequency by adjusting the width of the additional stubs. Hence, different bandwidths can be obtained where the bandwidth is reversely proportional to the width of the stubs. The filter with fractional bandwidth of about 66% is successfully realized on microstrip lines. The filter is simulated, and fabricated to demonstrate the proposed technique where excellent agreement is obtained. The filter shows low insertion loss of less than 1 dB and a flat group delay of about 0.25 n at the center frequency.