Introduction to transmission lines basic principles and applications of quarter-wavelength cables and impedance matching

1993 ◽  
Vol 5 (1) ◽  
pp. 57-86 ◽  
Author(s):  
Daniel D. Traficante
Keyword(s):  
Transmission Lines ◽  
Impedance Matching ◽  
Basic Principles ◽  
Quarter Wavelength

Miniature UWB Filter Using Three-Quarters Wavelength Resonator with Direct-Connected Feed Method

2012 ◽  
Vol 571 ◽  
pp. 721-724
Author(s):  
Cai Peng
Keyword(s):  
Transmission Lines ◽  
Linear Structure ◽  
Ultra Wideband ◽  
Input Output ◽  
Transmission Zeros ◽  
Full Wave ◽  
Quarter Wavelength ◽  
Ring Structures ◽  
Loss Characteristic ◽  
Better Than

A miniature ultra-wideband (UWB) bandpass filter using three-quarters wavelength resonators is presented in this paper. Direct-connected feed method is employed between the input/output ports and the resonators in order to overcome the shortcomings due to the gap-coupled feed method and produce two transmission zeros in the lower and upper stopbands. On the other hand, two quarter-wavelength matching transmission lines are introduced to the input/output ports to improve the reflection loss characteristic in the passband of the filter. In addition, the resonators are folded to be open ring structures, which are more miniaturized than the conventional linear structure. As a consequence, the filter is compact in size and exhibits good performance. The filter is successfully realized in theory and verified by full wave EM simulation, and simulated frequency response results show that the fabricated filter has an insertion loss of better than 1dB in the passband and two rejections of greater than 25dB in most of the stopbands.

Novel rat-race coupler design of arbitrary coupling coefficient using substrate integrated waveguide cavity

2018 ◽  
Vol 10 (8) ◽  
pp. 861-869 ◽  
Author(s):  
Min-Hua Ho ◽  
Yi-Hao Hong ◽  
Jen-Chih Li
Keyword(s):  
Transmission Lines ◽  
Coupling Coefficient ◽  
Substrate Integrated Waveguide ◽  
Cavity Field ◽  
Arbitrary Coupling ◽  
Degenerate Mode ◽  
Quarter Wavelength ◽  
Small Phase ◽  
Hybrid Coupler ◽  
Degenerate Modes

AbstractThe contribution of this paper is to propose a novel rat-race hybrid coupler of arbitrary coupling coefficient. Traditionally, the rat-race hybrid couplers are built by various loop-alike transmission-lines of multiple quarter-wavelength, and in this paper, we approach the coupler design by using a circular substrate integrated waveguide (SIW) cavity (SIWC). The employed SIWC supports two mutually orthogonal degenerate modes, and cavity field is formed by the two modes in an arbitrary weighting ratio which defines the proposed rat-race coupler's coupling coefficient. The cavity is excited by a microstrip combined coupling slot with the microstrip along a specifically chosen direction. The energy of each degenerate mode can be solely extracted by an associated subminiature version A (SMA) whose position is carefully determined. The isolation between the coupling slots is assured by their perpendicular layout, and the isolation between the SMA probes is obtained by the orthogonality of the two degenerate modes. Experiments are conducted on the 3- and 10-dB coupling coefficient samples to verify this novel rat-race coupler design. The measurements agree well with the simulations, and circuit's good performance is observed in terms of coupling precision, isolations, and small phase imbalances.

scholarly journals Closed-loop ring resonator topology for bandpass filter applications

2020 ◽  
Vol 17 (3) ◽  
pp. 1422
Author(s):  
Norfishah Ab Wahab ◽  
M. N. Md Tan ◽  
M. N. Hushim
Keyword(s):  
Transmission Lines ◽  
Closed Loop ◽  
Bandpass Filter ◽  
Ring Resonator ◽  
Single Mode ◽  
Ring Structure ◽  
Transmission Zeros ◽  
Quarter Wavelength ◽  
Coupled Lines ◽  
Loop Ring

<p class="Pa41">This paper presents a single mode pseudo-elliptic bandpass resonator based on closed-loop ring topology. The resonator is built from six quarter wavelength transmission lines to form a square closed-loop ring structure. This structure creates transmission zeros at the lower and upper sidebands so that high selectivity bandpass filter response is achieved. The advantage of this topology is that the design is less complex since no perturbation is needed on the ring lines for creation of transmission zeros. Higher-order filters can be constructed by introducing quarter-wavelength coupled-lines, coupled at both input and output of the closed-loop ring resonator. For proof of concept, the filters are designed at 10 GHz up to 3<sup>rd</sup> order, simulated using full-wave electromagnetic simulator on microstrip substrate, <em>FR-4</em> with characteristics given as <em>Ԑr </em>= 4.70, <em>h </em>= 1.499 mm and <em>tan δ </em>= 0.012.  The filters are simulated and responses are found to be agreeable with the proposed idea.</p>

U-Patch Antenna for RFID and Wireless Applications

2011 ◽  
Vol 324 ◽  
pp. 434-436
Author(s):  
R. Abi Saad ◽  
Zeina Melhem ◽  
Chadi Nader ◽  
Youssef Zaatar ◽  
Doumit Zaouk
Keyword(s):  
Radio Frequency Identification ◽  
Patch Antenna ◽  
Impedance Matching ◽  
Dual Band ◽  
Antenna Structure ◽  
Wireless Applications ◽  
Microstrip Patch ◽  
Additional Layer ◽  
Quarter Wavelength ◽  
Frequency Identification

in this paper, we propose a new multi-band patch antenna structure for embedded RFID (Radio Frequency Identification) readers and wireless communications. The proposed antenna is a dual band microstrip patch antenna using U-slot geometry. The operating frequencies of the proposed antenna are chosen as 2.4 and 0.9 (GHz), obtained by optimizing the physical dimensions of the U-slot. Several parameters have been investigated using Ansoft Designer software. The antenna is fed through a quarter wavelength transformer for impedance matching. An additional layer of alumina is added above the surface of the conductors to increase the performance of the antenna.

scholarly journals Wide CPW-Fed Multiband Wearable Monopole Antenna with Extended Grounds for GSM/WLAN/WiMAX Applications

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Danvir Mandal ◽  
S. S. Pattnaik
Keyword(s):  
Resonance Condition ◽  
Coplanar Waveguide ◽  
Impedance Matching ◽  
Monopole Antenna ◽  
Antenna Performance ◽  
Quarter Wavelength ◽  
Triangular Patch ◽  
Matching Structure ◽  
Standard Limit ◽  
Good Agreement

A novel wide coplanar waveguide- (CPW-) fed multiband wearable monopole antenna is presented. The multiband operation is achieved by generating slanted monopoles of different lengths from an isosceles triangular patch. The different operating frequencies of the proposed antenna are associated with the lengths of the slanted monopoles, which are determined under quarter wavelength resonance condition. The CPW line is used as a multiband impedance-matching structure. The two grounds are slightly extended for better impedance matching. The proposed antenna is designed to cover the 1800 MHz GSM, 2.4 GHz/5.2 GHz WLAN, and 3.5 GHz WiMAX bands. The measured peak gains and impedance bandwidths are about 4.18/3.83/2.6/2.94 dBi and 410/260/170/520 MHz for the 1550-1960 MHz/2.3-2.56 GHz/3.4-3.57 GHz/5.0-5.52 GHz bands, respectively. The calculated averaged specific absorption rate (SAR) values at all the resonant frequencies are well below the standard limit of 2 W/kg, which ensures its feasibility for wearable applications. The antenna performance under different bending configurations is investigated and the results are presented. The reflection coefficient characteristics of the proposed antenna is also measured for different on-arm conditions and the results are compared. A good agreement between experimental and simulation results validates the proposed design approach.

A New High Voltage Transmission Lines Deicer Based on Vibrations Principle

2013 ◽  
Vol 772 ◽  
pp. 604-607
Author(s):  
Jing Nie
Keyword(s):  
High Voltage ◽  
Transmission Lines ◽  
Social Benefits ◽  
Lead Wire ◽  
Ice Melting ◽  
Paper Briefly ◽  
Basic Principles ◽  
High Voltage Transmission Line ◽  
Pros And Cons ◽  
High Voltage Transmission

In recent years, for the high voltage transmission lines suffered serious Icing lead wire dancing, break and tower collapsed, domestic and foreign strengthened the study of high-voltage overhead line deicing methods and put forward a variety of line deicing methods. This paper first introduced thermal ice-melting method, mechanical deicing method, natural deicing method and several common deicing methods and analyzed the pros and cons of various deicing program. Based on the analysis of deicing methods for the high voltage transmission lines, a new and simple high voltage transmission line deicer is brought forward. This paper briefly discussed the basic principles and advantages of the device, providing a new way of thinking for the high voltage transmission lines deicing and having a certain value and social benefits.

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