China
Africa
Explore chapters and articles related to this topic
Wireless Building Blocks Using SiGe HBTs
Published in John D. Cressler, Circuits and Applications Using Silicon Heterostructure Devices, 2018
To the circuit designer, transmission line effects imply that impedance must also be closely controlled so that signal reflections and the ringing of pulse waveforms (or “signal integrity”) do not impair performance. For example, an ideal voltage amplifier (infinite input impedance, zero output impedance) would not be suitable as an interface to an RF antenna as power could not be efficiently transferred to or received from the antenna. Also, since interconnect cable lengths in a typical measurement setup for an RF circuit are approximately 1 m or more (about 0.2λ in electrical length at 1 GHz), transmission lines and their behavior must be understood in order to test and characterize RF and high-speed circuits.
T
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
transmission line filter i, j Z + (the set of nonnegative integers) is defined as follows: translator an unattended television or FM broadcast repeater that receives a distant signal and retransmits the picture and/or audio locally on another channel. transmission (1) the act of sending information from one location to another. (2) transformation of an optical wave incident on a surface that passes a portion of the wave to the medium behind the surface. (3) that class of electric power system work which is concerned with the transport of electric power from the generator to the area of consumption. The circuits of interest typically extend at the generating station and terminate at the local substation. transmission coefficient a number that describes the relative amplitude and phase of the transmitted wave with respect to the incident wave. The term is usually used in the context of wave transmission at a material interface or transmission line. transmission grating a diffraction grating that operates in transmission, i.e., the diffracted light is obtained by shining light through the grating. transmission line (1) an arrangement of two or more conductors used to convey electromagnetic energy from one point to another. (2) conductive connections that guide signal power between circuit elements. transmission line coupler passive coupler composed of two or more transmissions spaced closely together where the proximity of the transmission lines allows signals to be coupled or transferred in part from one line to the other. The electrical length of the transmission lines is usually one quarter of a wavelength. transmission line filter a microwave device that is made up of sections of transmission lines so as to act as a filter in the microwave frequency range.
Transmission Line Time-Domain Analysis and Signal Integrity
Published in Bogdan M. Wilamowski, J. David Irwin, Fundamentals of Industrial Electronics, 2018
Edward Wheeler, Jianjian Song, David R. Voltmer
Speaking more generally, study of quasi-statics shows that transmission line models are not needed if the electrical length of the conductors is short. In the frequency-domain, electrical length is proportional to the ratio of conductor length (ℓ) to wavelength (λ). [EETR60] In the time domain, it is proportional to the ratio propagation delay-to-signal rise time. For lines that are electrically short—that is, when λ ≫ ℓ or when tr ≫ td—wave effects are negligible and transmission line models are unnecessary.
Design and analysis of double-layer parasitic split-ring resonator based on O-shaped engraved microstrip based radiating structure for 5G, WiMAX, WLAN and LTE applications
Published in Waves in Random and Complex Media, 2023
Sunil P. Lavadiya, M. M. Kamruzzaman, T. Senthil Kumar, Beulah Jackson, Shobhit K. Patel
In the proposed paper, we are mainly concentrating on frequency reconfigurability. Frequency reconfigurability depends on the structure’s electrical length; by changing the electrical length, the resonance frequency has deviated, and reconfigurability is achieved [3,11]. There are four methods available to achieve this. First is using switches like PIN diode, field-effect transistors, optical switches, and RF-MEMS that switch the operating frequency. The second method is variable reactive loading in that smoothly switching between different frequency bands is possible. The third method is effective dimension change by mechanical structure changes in that the magnetic actuator and piezoelectric actuator help to switch broad frequency bands. The fourth is a material change in that changing material deviates permeability and permittivity that differs the resonance frequency. Overall electrical and mechanical antenna structures require complex designs that reduce the radiation effect due to the parasitic impact [12]. Article [12] represents the method to achieve low dielectric loss and better tunability. The ferromagnetic material of barium strontium titanate (BST) varactor is useful for the miniaturized antenna, microwave devices, and reconfigurable antennas. The mechanism of the PIN diode is controlled by applying proper bias voltage on it to make it ON (short circuit) and OFF (open circuit). Similarly, the switching mechanism for connecting and disconnecting specific parts of the structure is always challenging because of rapid switching.
A novel compact folded zeroth-order resonant antenna for Internet of Things USB dongle applications
Published in Electromagnetics, 2020
Hassan Tariq Chattha, Farooq A. Tahir, Zain B. Khalid, Aamir Rashid
The metamaterials, having negative permeability and negative permittivity concurrently, generally known as Left-Handed (LH) materials, are given a great consideration and deliberation in engineering and scientific research for developing new and novel solutions and applications due to their unique characteristics (Lai, Itoh, and Caloz 2004). LH materials are considered a generic model of Composite Right/Left-Handed (CRLH) structures. Zeroth-order resonance is a special type of Composite Right/Left-Handed Transmission Line (TL) where electrical length becomes zero and the resonant frequency of antenna is dependent solely on value of realized capacitance and inductance while being free from the size of antenna (Sanada, Caloz, and Itoh 2004). Composite Right/Left-Handed (CRLH) transmission lines are found in literature for different antenna designs for achieving certain desired characteristics (Chi and Shih 2004; Lee, Woo, and Nam 2015).
Heuristic Topology for Designing Reconfigurable Balun Active Filter for Frequency, Bandwidth and Power Division Ratio
Published in IETE Journal of Research, 2023
Shikha Swaroop Sharma, Anjini Kumar Tiwary
Figure 1 shows a three-stage planar Marchand balun filter. This circuit is designed using a RT/Duroid 5880 substrate with permeability (ϵr) = 2.2, height (h) = 0.8025 mm and loss tangent (tanδ) = 0.0009. The design is based on the traditional Marchand balun theory, in which two coupled-line sections that are short-ended on one side and open-ended on the other side, as shown in Figure 2. The even- and odd-mode impedances and electrical length of each coupled-line section are Zoe, Zoo, and θo, respectively. The electrical length θo is quarter wavelength at the center frequency foi.e. 1.9 GHz.