Dual Composite Right/left-handed Research Articles

Design of Phase Shifters with Enhanced Selectivity and Miniaturized Size Using D-CRLH Resonator

This paper proposes and demonstrates a novel filtering phase shifter with a compact size and good frequency selectivity using two dual composite right/left-handed (D-CRLH) resonators. Firstly, the study analyzes the D-CRLH structure to gain insights into its unique properties, providing a physical understanding for subsequent design procedures. Then, an ad hoc systematic design procedure for the D-CRLH phase shifter is discussed in detail. Different from the traditional phase shifter, the innovative integration of D-CRLH structure in phase shifters enables its advantages in the flexible realization of good in-band frequency selectivity and compact size. This advantageous utilization of the D-CRLH structure distinguishes our proposed phase shifter from conventional implementations. Finally, to demonstrate the feasibility of the proposed structure, we design, fabricate, and measure a prototype of the filtering phase shifter with a 90° phase shift. The comparison between simulation and measurement results shows good agreement, thereby confirming the effectiveness of both the new filtering phase shifter and the presented design procedure. Through this comprehensive investigation, our work showcases a promising solution for achieving compact size, good frequency selectivity, and reliable performance in phase shifter design.

3-D printed dual-band, dual-sense circularly polarized dielectric resonator antenna with a bandstop filtering response using planar via-free D-CRLH feeding network

A novel concept to design a dual-band, dual-sense circularly polarized (CP) antenna with a bandstop filtering response is presented by adopting an elaborate-designed irregular-shaped dielectric resonator (ISDR) and a dual-composite right/left-handed (D-CRLH)-based feeding network. First, the TEy111 and TEy113 modes of a rectangular DR (rDR) are simultaneously excited using an offset feeding slot, to realize the dual-band, linearly polarized (LP) operation in the x-direction. To eliminate the effects of the offset feeding on antenna performance, two types of edge-cuts and an impedance transformer are introduced. Secondly, another microstrip line and offset feeding slot are utilized to excite TEx111 and TEx113 modes of the DRA, obtaining dual-LP in two bands, and the corner truncation is introduced to reduce the cross-polarized field. Accordingly, a dual-band, dual-LP DRA with boresight radiation and low cross-polarization is achieved. After that, building on this design, a dual-band feeding network based on the D-CRLH resonator is employed to further implement the dual-sense CP operation. Finally, the ISDR is manufactured using 3-D printed technology for demonstration. The measured results show that the proposed antenna obtains a 3-dB axial ratio (AR) bandwidth of 9.3 % for the left-hand circular polarization (LHCP) at the lower band and 3.6 % for the right-hand circular polarization (RHCP) at the upper band. Moreover, the proposed antenna also features good suppression between two bands as the D-CRLH resonator offers a stopband filtering effect.

Dual composite right/left‐handed unit with improved spurious performance and its application in wide‐stopband bandpass filter

AbstractA compact dual composite right/left‐handed (D‐CRLH) unit with improved spurious performance is presented in this study. The proposed D‐CRLH unit consists of an interdigital capacitance (IDC) and a microstrip section inductor (MSI). Compared with the traditional IDC, the proposed IDC is improved by connecting the ends of the alternate fingers through the metallic paths on the back of the substrate. Thus, the spurious resonance at low frequency is eliminated and the usable bandwidth of the IDC is extended. The meander slots are also exploited in each finger of the IDC to increase the series capacitance, which contributes to reducing the circuit size. Furthermore, the proposed D‐CRLH unit is applied in the wide stopband bandpass filter (BPF) design to demonstrate its practicability. The BPF is fabricated and measured for demonstration. The measured results are in good agreement with the simulated results.

Compact antipodal Vivaldi antenna design with gain enhancement and notched-band characteristics based on D-CRLH metamaterial

A novel compact ultra-wide band (UWB) antipodal Vivaldi antenna with band notched is presented in this communication. T-shaped slot is introduced to extend the lower end limitation of the frequency band from 1.65 GHz to 1.25 GHz, the miniaturization of the antenna is realized. Then a new thought of the gain enhancement, namely the substrate cutout (SCO) is demonstrated to increase antenna gain, which makes the electromagnetic wave get rid of the bondage of the substrate, reducing the edge diffraction, and thus radiates more effectively, without changing the overall dimension of the antenna. The advantage is of great value in limited space especially. Then a compact unit cell based on Dual Composite Right-Left Handed (D-CRLH) metamaterial is proposed to realize the notched band characteristics in the WLAN band (4.95–5.15 GHz). In addition, the passband would be less affected by the notched band due to the sharp transition band between notched and operating band. Finally, the antenna is successfully simulated and measured, it shows broadband matched impedance, stable gain and radiation pattern over the operating band. The experimental results are also given and show a good agreement with the simulated results.

Compact Dual-Band Wilkinson Power Divider Design Using Via-Free D-CRLH Resonators for Beidou Navigation Satellite System

A compact dual-band Wilkinson power divider (WPD) using the via-free dual-composite right/left-handed (D-CRLH) resonators is presented for application in the Beidou navigation satellite system in this brief. First, by establishing an equivalent circuit model and using Bloch theory, a dual-band resonator is further analyzed to gain insight into its working mechanism, which can exhibit −90° phase shift at lower frequencies and +90° phase shift at upper frequencies, respectively. Then, to facilitate the design, ignoring parasitic parameters, a simplified circuit model retaining the physical meaning is presented, and the closed-form formulas for determining lumped element values of a dual-band characteristic are derived. Next, there is a significant rejection performance between two operating frequencies due to the inherent band-stop filtering effect of the D-CRLH resonator. Following that, the WPD is verified through experiments, showing excellent performance. Finally, based on this property, a dual-band feeding network (FN) is constructed by the combination of a WPD and a phase shifter with the proposed resonator. The simulated and measured results are found in good agreement with each other, which further demonstrated our proposed design conception.

A compact dual-band D-CRLH-based antenna with self-isolation functionality

AbstractThis paper presents a compact dual-band filtering antenna without extra employing of filter structures. The antenna is designed using a planar dual-composite right/left-handed (D-CRLH) transmission line unit cell, where the filtering function is achieved through current cancellation between the D-CRLH resonators. The antenna is designed to function at 3.0 and 5.1 GHz, which can serve different WLAN applications. The antenna is a co-planar waveguide fed with a very compact size of only 30 × 16 mm2. Compared to the conventional patch antenna, the antenna size is only 17% at 3.0 GHz and 31% at 5.1 GHz. Despite the small size, the antenna preserves a good omni-directional radiation pattern at the two resonant frequencies with a measured realized gain of 2 and 2.7 dB, respectively. At the stopband in-between the two resonant bands, the reflection coefficient is almost 0 dB at 4.25 GHz and complete non-radiation is proved with a −11 dB measured realized gain. The different antenna filtering functions are verified by full-wave simulation and measurements.

Design and Analysis of a Bandpass Filter Using Dual Composite Right/Left Handed (D-CRLH) Transmission Line Showing Bandwidth Enhancement

Design and Analysis of a Bandpass Filter Using Dual Composite Right/Left Handed (D-CRLH) Transmission Line Showing Bandwidth Enhancement

Miniaturized High Temperature Superconducting Bandpass Filter Based on D-CRLH Resonators

In this paper, a novel high temperature superconducting (HTS) dual composite right/left-handed (D-CRLH) resonator is proposed, which is constructed by microstrip spiral coupled lines and microstrip high-impedance lines. Moreover, by using an equivalent circuit model and a admittance matrix method, the characteristics of the D-CRLH resonator is obtained and analyzed, which makes it suitable for implementing the miniaturized high-performance filter. For demonstration, a second-order D-CRLH bandpass filter is designed on a 0.5-mm-thick MgO wafer with double sided YBa <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">7</sub> films. Multitransmission zeros are obtained in the stopband of the filter, improving the selectivity and stopband characteristics of the filter. Good agreement between the measurements and design goals can be observed.

Active Dual-Band Power Divider and Active Quad-Plexer Based on Traveling Wave Amplification and D-CRLH Transmission Line

A travelling wave structure with two novel functionalities is presented in this brief. The structure benefits from the nonlinear dispersion relation of dual-composite right/left-handed (D-CRLH) transmission line (TL). It consists of two distributed amplifiers (DAs) that have one common gate line and two drain lines. The conventional microstrip TL is used for gate line while the D-CRLH unit cells (UCs) are used to make the drain TLs. When the operating frequencies of D-CRLH TLs of both drain lines are the same, the structure acts as a directional dual-band active power divider (PD). The RF input signal depending on the input signal frequency, is divided into two forward or reverse output ports after amplification. If the D-CRLH TLs have different operating frequencies with no common band, the structure can act as an active quad-plexer or directional quad band amplifier. In this situation, four amplified signals with different frequency bands can be extracted from four different physical output ports. Analysis and design procedure of the structure is provided and a fabricated prototype is measured which shows a good agreement between the simulated results and the measurement results.

Novel Design of Miniaturized Filtering Power Dividers Using Dual-Composite Right-/Left-Handed Resonators

One kind of miniaturized filtering power divider (FPD) with a new topology is proposed. For previously published FPDs, the isolation resistors were usually added with additional quarter-wave ( $\lambda $ /4) transmission lines for output isolation. In this paper, $\lambda $ /4 transmission lines are removed, and the resistor is added to the loaded resonator for the miniaturized design. By regarding the input external quality factor ( $Q_{e\text {-in}}$ ) as an admittance inverter, the indispensable 90° delay can be easily realized. To further improve the miniaturization, the dual-composite right-/left-handed (D-CRLH) resonators are adopted; therefore, the overall sizes of the resulting FPDs can be smaller than $0.012\lambda _{g}^{2}$ . Moreover, the equivalent circuit of the proposed FPD is investigated for the performance improvement. Input $Q_{e\text {-in}}$ should be double of output $Q_{e\text {-out}}$ for good matching, and good isolation can be obtained by appropriately utilizing $Q_{e\text {-in}}$ . For demonstration, three D-CRLH FPDs are designed for narrowband, wideband, and dual-band applications. Satisfactory agreements between the measured results and theoretical expectations are observed, verifying the validity of the proposed design concepts.

Compact D-CRLH resonator for low-pass filter with wide rejection band, high roll-off, and transmission zeros

AbstractA compact low-pass filter (LPF) with wide rejection band based on T-type circuit of an enhanced dual composite right-/left-handed (D-CRLH) resonator is presented in this paper. The resonator has only one cell with series and parallel tank circuit. The parallel LC tank circuit has been realized by an interdigital capacitor and one shorted finger, whereas its series LC tank circuit is realized by an air gap capacitance and a short circuit stub. The filter has wide rejection band bandwidth with three transmission zeros (TZs). The filter bandwidth and TZs frequencies are controlled by the D-CRLH element values. The results of the proposed filter demonstrate minimum insertion loss in passband, high roll-off rate, and good figure of merit. The measured results are in good agreement with the simulated results. The detailed filter design is discussed in terms of circuit modeling, dispersion analysis, and full-wave simulation. Finally, the filter size is compact (0.10 λg × 0.15 λg) at cut-off frequency.

Characteristics of Dual Composite Right/Left-Handed Unit Cell and Its Applications to Bandpass Filter Design

The characteristics of a modified dual composite right/left-handed (D-CRLH) unit cell is investigated, which can be applied to design bandpass filters. The proposed unit cell is very compact and contains ten structural variables, which provides large design flexibility to realize different frequency responses. To assist the design of D-CRLH unit cells, the resonant characteristics are analyzed, and the design strategies for performance improvements are given accordingly. Furthermore, the design method of D-CRLH bandpass filters is introduced, with which the desired performance can be obtained by dimensions modifications of adopted resonators. For demonstration, three D-CRLH bandpass filters aimed at different performance are designed and experimentally verified. Good agreement between the measurements and design goals can be observed.

Dual CRLH Based Band Stop Filter Using Conductor-Backed Defected Coplanar Waveguide

A band stop filter is proposed with cascading unit cells that are based on a dual composite right/left-handed (D-CRLH) conductor-backed coplanar waveguide. The parameters of the unit cell have been analyzed to confirm the behavior of each component for the equivalent circuit of the cell. We simulated the dispersion characteristics and energy distribution and have determined that the unit cell has a D-CRLH property. The band stop filter was implemented by symmetrically cascading two of the proposed unit cells. The experimental results for the band stop filter revealed a band rejection performance of 32 dB and a return loss of 0.35 dB in the stopband frequency range from 869MHz to 954MHz. Finally, we show that there is a good agreement in the experimental results and those obtained through the simulations.

CPW-Fed Multiband Monopole Antenna Loaded With DCRLH-TL Unit Cell

A coplanar waveguide (CPW)-fed multiband monopole antenna based on loading one dual composite right/left-handed (DCRLH) transmission line (TL) unit cell is presented. The antenna works at 3.22 GHz, 4.57 GHz, and 5.71 GHz. The first resonant frequency (3.22 GHz) is a little lower than the first resonance (3.38 GHz) of the corresponding conventional monopole, the second (4.42 GHz) is much lower than the second resonance (9 GHz) of the conventional monopole, and the third one achieves the zeroth-order (ZOR) resonance. Also the electromagnetic (EM) simulation results demonstrate that the proposed antenna has satisfactory omni-directional radiation patterns with reasonable gains. Finally the antenna is fabricated and measured; measurements and EM simulations are in good agreement.

STUB BASED EQUIVALENT CIRCUIT MODELS FOR EVEN/ODD MODE DUAL CRLH UNIT CELLS

The theory of even/odd mode based dual composite right/left handed (D-CRLH) unit cells is developed, and a unifled modeling approach based on stubs is presented. The theory shows that these unit cells will have left-handed behavior if the even and odd mode corresponding stubs have dual behavior. Several unit cells are investigated. The proposed models agree with EM simulations. Experimental results conflrm the presented theory.

DESIGN OF QUAD-BAND FILTER BASED ON THE IMPROVED VERSIONS OF DCRLH CELL

In this article, a realization version of quad-band fllter is flrstly proposed, and it is the cascaded structure composed of the shunt open-circuit DCRLH (dual composite right/left-handed) cell and the shunt short-circuit DCRLH cell. The above two cells are initially proposed here in order to improve the inherent limitations of the microstrip DCRLH cell. It is demonstrated that the matching performance and frequency selectivity of these two cells are both better than those of the microstrip DCRLH cell. It is more important that both the cells exhibit three transmission zeros within the given frequency band, and any of them is of great potential to be applied in the design of quad-band fllters. In order to get su-cient design freedom, we utilize the cascade connection version based on the shunt open/short-circuit DCRLH cells. Whereas, only the flrst and second transmission zeros of both the shunt open/short-circuit DCRLH cells are explored. Both the simulated and measured results indicate that the proposed design method is right and efiective.

Development of a Dual Composite Right / Left Handed (D-CRLH) Differential Transmission Line Common Mode Filter

Development of a Dual Composite Right / Left Handed (D-CRLH) Differential Transmission Line Common Mode Filter

Dual-composite right–left-handed transmission lines for the design of compact diplexers

In this study, the use of dual-composite right–left-handed (D-CRLH) transmission lines is proposed for the design of diplexers. The D-CRLH diplexers present advantages over conventional diplexers such as smaller size (especially in the ultra high frequency band). The design procedure and the design equations are presented in this paper. The non-linear phase response of a D-CRLH transmission line has been used to design diplexers at any arbitrary frequencies. Finally, two diplexers have been designed and manufactured: one for quite near frequencies and the other for further ones. The simulation results show good agreement with the measurements. A sensitivity analysis has been provided to show the robustness of this kind of circuits.

A PLANAR D-CRLH AND ITS APPLICATION TO BANDSTOP FILTER AND LEAKY-WAVE ANTENNA

A planar dual-composite right/left-handed (D-CRLH) transmission line (TL) structure is proposed. The characteristics such as dispersion relation and frequency response of this D-CRLH TL are analyzed by equivalent circuit analysis, Bloch-Floquet theory, full wave simulation and experiment. To demonstrate applications of the proposed structure, both bandstop fllter and leaky-wave antenna are designed and implemented by the conventional print circuit board technology. The fabricated fllter has a broad application because of its planar structure, small size and tunable stopband. The measured results also suggest that the leaky-wave antenna based on the D-CRLH concept can ofier a scanning angle covering almost backflre-to-endflre directions.

Metamaterial 전송선을 이용한 이중 대역 저지 필터

본 논문에서는 Metamaterial 전송선을 이용한 이중 대역 저지 필터를 제안하고 제작, 측정하였다. 이는 Wilkinson Power Divider의 형태를 바탕으로, 입력 단자에 신호를 인가하면 동일한 크기와 위상을 갖는 신호로 나눠진다. 이를 각각의 전송선에서 CRLH(Composite Right/Left-Handed) 구조와 D-CRLH(Dual Composite Right/Left-Handed) 구조를 이용하여 위상 변화를 유도한다. 본 논문에서는 TDMB 주파수 대역인 195 MHz와 DVB-T/H 주파수 대역인 670 MHz 대역에 대해 저지 대역 특성을 유도하였다. 이를 통해 제작한 필터의 크기는 <TEX>$30{\times}15\;mm$</TEX> 이며, -10 dB를 기준으로 대역폭을 측정한 결과 각각의 주파수 대역에서 73 %, 50 %의 결과를 얻을 수 있었다. This raper proposes a dual-bandstop filter, which is based on a metamaterial transmission line using the composite right/left-handed (CRLH) and dual composite right/left-handed (D-CRLH) structures. The metamaterial structure is used for miniaturization and dual-bandstop operation at the TDMB frequency range (195 MHz) and DVB-T/H frequency range (670 MHz). The size of the proposed filter is <TEX>$30{\times}15\;mm$</TEX>, and the -10 dB bandstop fractional bandwidth is approximately 73 % and 50 % at each frequency, respectively.