Planar Artificial Transmission Lines Research Articles

Research Status and Design Method of Slow Wave Transmission Lines

Abstract In this paper, the research status and implementation methods of slow wave transmission lines are analyzed. Slow wave transmission lines are distinguished from other planar artificial transmission lines by the positive and negative values of equivalent permittivity and permeability. On this basis, the realization method is summarized through the analysis of equivalent dielectric constant and permeability. The methods of multi-layer dielectrics, periodically loaded capacitors (inductors or branches), cascaded cells and defective ground structures are summarized to increase the value of e and μ, so as to reduce the phase velocity of electromagnetic wave and realize slow wave transmission line. It provides a reference for the design and application of slow wave transmission lines.

Parameter Extraction Method for Planar Artificial Transmission Line

Abstract In this paper, a method for extracting parameters of planar artificial transmission line is proposed. On the one hand, the Z parameters are solved by S parameters, and then the equivalent circuit parameters are obtained directly by S parameters through the relationship between Z parameters and lumped elements of equivalent network model. On the other hand, the expressions for calculating attenuation constant α, phase shift constant β and characteristic impedance Zc of transmission line by S parameters are obtained, which are planar artificial transmission. Mathematical methods for analysis of transmission line model and parameter extraction and summary.

Application Status of Planar Artificial Transmission Line in Antenna Design

Abstract Using the dispersion characteristics and media characteristics of planar artificial transmission lines, we not only can realize the miniaturization, dual/multi-frequency, broadband of components in antenna-feeder systems, but also can realize new functions that conventional transmission lines have not in antenna-feeder systems. In this paper, the application of planar artificial transmission line in the design of multi-functional antenna, which provides a reference for the future design, is analyzed.

PLANAR ULTRA-WIDEBAND PHASE SHIFTER USING A NOVEL TYPE OF ARTIFICIAL TRANSMISSION LINE

An ultra-wide band 45 ◦ phase shifter based on a new planar artificial transmission line which can be used for UWB communication systems is presented. The planar artificial transmission line is composed of host line, grounded interdigital capacitors and meandered-line inductors. The phase shifter was measured to have a bandwidth about 114.7% (2.9 GHz to 10.7 GHz) for a maximum phase deviation of 2.9 ◦ , a maximum insertion loss of 1.2 dB, a minimum return loss of 13 dB and a compact size of 16.35 mm × 5.2 mm.

Compact Two-Section Half-Wave Balun Based on Planar Artificial Transmission Lines

Artificial transmission lines are realized by a series of meandered-line inductors, parallel-plate capacitors, and interdigital capacitors, which belong to metamaterial transmission lines. An ameliorated artificial transmission line is proposed to realize a low characteristic impedance transmission line. A two-section half-wave balun at 900 MHz is designed, fabricated, and measured in this paper. The compact balun is based on conventional and ameliorated planar artificial transmission lines instead of microstrip transmission lines. The main advantage of the proposed balun is its size reduction, which occupies only about 10% of a conventional one. Measured results match well with theory and simulation. The balun features excellent amplitude and phase balance in microwave power combining and a reasonable bandwidth of the return loss as well.

A Miniaturized Microstrip-to-Coplanar-Strip Transition Loaded with Artificial Transmission Lines and 2.4-GHz Antenna Application

A miniaturized microstrip-to-coplanar strip transition and its antenna application are presented in this letter. A composite right/left-handed transmission line and planar artificial transmission lines are used to design the transition in the 2.4-GHz band and to balance the output of the transition over a wider frequency range. In addition, the occupied area of the transition is only 0.087λg <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . The 3-dB back-to-back insertion loss bandwidth is around 84%. Based on the proposed transition, a quasi-Yagi antenna is demonstrated. The impedance bandwidth is 30.3%. The antenna offers excellent endfire radiation performance. The maximum gain and front-to-back ratio are 5.1 dBi and 21 dB, respectively, at the endfire direction in the operating band. The design process and the measured results of the proposed design are presented in detail.

Response to “Comments on “Planar Artificial Transmission Lines Loading for Miniturization of RFID Printed Quasi-Yagi Antenna””

The He et al. comment that claimed the ATL segments contribute little in the antenna radiation characteristics has been investigated and rejected with different clear reasons such as current distribution, radiation pattern, and input impedance.

Comments on “Planar Artificial Transmission Lines Loading for Miniturization of RFID Printed Quasi-Yagi Antenna”

In a recent paper by Hajizadeh et al. [1], the authors employed the artificial transmission lines (ATLs) proposed in [2] as the radiating elements of a quasi-Yagi antenna for miniaturization. The proposed structure (with discontinuities on one side and a finite ground on the other side of the substrate) is applied to replacing the open-ended transmission line in each arm of the original dipole antenna.

Planar Artificial Transmission Lines Loading for Miniturization of RFID Printed Quasi-Yagi Antenna

A compact omnidirectional printed quasi-Yagi antenna for RFID reader application is presented. To reduce the size of the antenna, the radiating elements of the quasi-Yagi antenna are replaced by artificial transmission lines (ATLs). The proposed antenna that operates at 915 MHz has a substrate size of 52×77mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , which shows more than 76.24% size reduction in comparison to the previously reported compact Yagi antenna. At the center frequency, the antenna has an input impedance of 46.66- <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">j</i> 4.27 Ω, radiation efficiency of 98.2%, and a gain of 1.84 dBi. The experimental data are in good agreement with the simulation results.

Compact broadband quadrature hybrid coupler using planar artificial transmission line

A novel compact size broadband quadrature hybrid coupler based on a planar artificial transmission line which can be used for WLAN application at 2.4 GHz is presented. The planar artificial transmission line is composed with both a dual transmission line and the Π-model technique. The occupied size of the proposed broadband hybrid coupler is merely 47% of the size of a conventional design. The compact size coupler demonstrates well-behaved wideband response and good agreement with measurement.

Compact capacitive compensated directional coupler using planar artificial transmission lines

A novel compact directional coupler based on planar artificial transmission lines is proposed. Interdigital capacitors are introduced to compensate for the odd-mode phase velocity in order to achieve a high directivity. The size of this proposed coupler is about 25% that of a conventional one. A 20 dB directional coupler at 900 MHz has been designed and fabricated. The directivity reaches 36 dB at the centre frequency. The design, simulation and measurements are presented.

A Miniaturized Dual-band Power Divider with Harmonic Suppression for Gsm Applications

In this paper, a miniaturized dual-band power divider based on artificial transmission lines is proposed for GSM applications. The design consists of four sections of recently developed planar artificial transmission lines, an LC tank circuit in shunt, and an isolation resistor. The experimental results show that the proposed configuration has good performance at both 0.9 GHz and 1.8 GHz. Meanwhile, it achieves a significant size reduction compared to traditional dual-band planar power dividers. At the center frequency 1.35 GHz, the dimension of the proposed dual-band power divider is only 43 mm × 21 mm, or equivalently 0.29λg × 0.14λg. With the harmonic suppression nature of artificial transmission lines and the shunt LC tank, the wideband response of the proposed dual-band power divider reveals good harmonics suppression.

A New Planar Artificial Transmission Line and Its Applications to a Miniaturized Butler Matrix

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A miniaturized quadrature hybrid coupler, a rat-race coupler, and a 4 <formula><tex>$\times$</tex></formula> 4 Butler matrix based on a newly proposed planar artificial transmission line are presented in this paper for application in ultra-high-frequency (UHF) radio-frequency identification (RFID) systems. This planar artificial transmission line is composed of microstrip quasi-lumped elements and their discontinuities and is capable of synthesizing microstrip lines with various characteristic impedances and electrical lengths. At the center frequency of the UHF RFID system, the occupied sizes of the proposed quadrature hybrid and rat-race couplers are merely 27% and 9% of those of the conventional designs. The miniaturized couplers demonstrate well-behaved wideband responses with no spurious harmonics up to two octaves. The measured results reveal excellent agreement with the simulations. Additionally, a 4<formula formulatype="inline"><tex>$\,\times\,$</tex></formula>4 Butler matrix, which may occupy a large amount of circuit area in conventional designs, has been successfully miniaturized with the help of the proposed artificial transmission line. The circuit size of the Butler matrix is merely 21% of that of a conventional design. The experimental results show that the proposed Butler matrix features good phase control, nearly equal power splitting, and compact size and is therefore applicable to the reader modules in various RFID systems. </para>