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Computer-Aided Design of Microwave Circuitry
Published in Mike Golio, Commercial Wireless Circuits and Components Handbook, 2018
Harmonic balance is used when the circuit is driven by periodic sources and when the design parameters, input and output, are specified in the frequency domain. The assumed periodicity of the circuit response avoids the need to compute the circuit response from time zero until the steady-state response is obtained. Therefore, much less computer time is required to predict the circuit response. Since the harmonic balance techniques were developed specifically to aid the microwave designer in the design of nonlinear circuits, the available programs are custom tailored to provide the results in a format familiar to the designer. For example, the input source for an amplifier can be swept in both frequency and power, and nonlinear parameters such as gain, 1 db compression point, saturated power output, power-added efficiency, and harmonic levels can all be displayed in a graphical or text form. Indeed these parameters are all natural artifacts of the computations. Other parameters that can easily be computed are intermodulation products, third order intercept point, noise side bands, and mixer conversion.
Nonlinear Circuit Analysis Methods
Published in Jingchang Nan, Mingming Gao, Nonlinear Modeling Analysis and Predistortion Algorithm Research of Radio Frequency Power Amplifiers, 2021
Solid state microwave devices are all nonlinear to some extent. In a communication PA, any nonlinearity of phase and amplitude in a voltage transmission waveform must be minimized to protect the waveform and spectral content of the signal. However, limiting amplifiers, oscillators, frequency multipliers and mixers rely on the nonlinearities of devices to obtain appropriate operations. In all cases, a complete circuit analysis on these devices requires nonlinear device models and analytical methods to extract device effects, that is, to analyze and obtain the interactions of model circuits. Harmonic balance method has a wide range of applications and can be used in microwave nonlinear circuits such as mixers, frequency multipliers and PAs.
Multiconductor Transmission Lines
Published in Wai-Kai Chen, Feedback, Nonlinear, and Distributed Circuits, 2018
It would be a formidable task to give a comprehensive overview of all the methods that are actually used for the time domain analysis of MTL. In the remaining part of this paragraph a very short overview (both for uniform and nonuniform structures) is presented along with some references. In the Case of linear loads and drivers, frequency domain methods in combination with (fast) Fourier transform techniques are certainly most effective [5-7]. In the presence of nonlinear loads and drivers other approaches must be used. Simulations based on harmonic balance techniques [8,9] are, again, mainly frequency domain methods. All signals are approximated by a finite sum of harmonics and the nonlinear loads and drivers are taken into account by converting their time domain behavior to the frequency domain. Kirchhoff laws are then imposed for each harmonic in an iterative way. Harmonic balance techniques are not very well suited for transient analysis or in the presence of strong nonlinearities, but are excellent for mixers, amplifiers, filters, etc. Many recent efforts were directed toward the development of time domain simulation methods (for both uniform and nonuniform interconnection structures) based on advanced convolution-type approaches. It is, of course, impossible to picture all the ramifications in this research field. We refer the reader to a recent special issue of IEEE Circuits and Systems Transactions [10], to the “Simulation techniques for passive devices and structures” section of a special issue of IEEE Microwave Theory and Techniques Transactions [11], and to a 1994 special issue of the Analog Integrated Circuits and Signal Processing Journal [12] and to the wealth of references therein.
Design and simulation of a novel 3-point star rectifying antenna for RF energy harvesting at 2.4 GHz
Published in Cogent Engineering, 2021
J. O Olowoleni, C. O. A Awosope, A. U Adoghe, Okoyeigbo Obinna, Udochukwu Ebubechukwu Udo
As with the antenna, the rectifier circuit was designed and optimized for an FR4 substrate (dielectric constant = 4.6, Substrate Height = 1.6 mm, Thickness = 0.7 mil, Tangential Losses = 0.001) using Advance Design System (ADS) simulation software. A greinacher voltage doubler configuration was adopted in the design and the conversion efficiency was simulated with respect to three different load impedances at a range of load at range of 10dBm to 34dBm of the input power. This was aided by the use of ADS parameter sweep simulation controller, alongside the harmonic balance simulation controller. Harmonic balance simulation makes it possible to simulate circuits with multiple input frequencies. It also provides for the calculation of the magnitude and phase of currents or voltage in a potentially non-linear circuit. The ADS “Line Calc” tool was used in generating optimized values for the length and width of the respective microstrip line (MLIN) components in the circuit.
The application of reduced space harmonic balance method for the nonlinear vibration problem in rotor dynamics
Published in Mechanics Based Design of Structures and Machines, 2019
The constrained optimization harmonic balance method (Liao, 2016; Liao and Sun, 2013) which is developed to calculate the unknown Fourier coefficients and resonant frequency simultaneously belongs to the simultaneous optimization method. It is a suitable candidate to solve the nonlinear dynamics problems. However, the mentioned method raises several questions. The optimization problem would become much more difficult when the harmonic balance equations are treated as nonlinear constraints. Moreover, the computation of the Hessian matrix becomes prohibitively expensive as the optimization problem size grows. Consequently, the burden of computation increases due to the increase of system dimension. Therefore, an adequate treatment of the large system of nonlinear equality constraints is required, which motivates the search for new approaches.
A nonlinear optimization bifurcation tracking method for periodic solution of nonlinear systems
Published in Mechanics Based Design of Structures and Machines, 2023
The harmonic balance method is a well-known frequency domain technique for dynamic systems, which has a huge advantage for modeling nonlinear vibration problems. There is a vast literature on the HBM. For example, Liao and Sun (2013) and Liao (2016) proposed the constrained optimization harmonic balance method in order to search the worst case resonance response. Recently, the reduced space approach is investigated in Liao (2019) to circumvent the drawbacks such as the computational efficiency of the previous works.