The memristor has long been presented as the fourth fundamental circuit element alongside the resistor, the capacitor, and the inductor. As the future of computing heads toward neuromorphic circuits, there has been a renewed interest in the modeling and simulation of memristors which have emerged as promising key components in the design of these systems. Despite such critical applications, very few models have been presented in the literature that allow for the automated and flexible integration of memristors in different simulators. In this article, three different models of the memristor are presented using the modified nodal analysis (MNA) formulation technique. Each stamp is tested and compared with a theoretical model of the memristor. Simulations are also performed on a memristor-based active high-pass filter circuit to demonstrate the accuracy of the model.

Sensitivity analysis is a critically important aspect in the simulation of integrated circuits. It allows the designer to perform vital tasks such as circuit optimization and design space exploration. Recently, an efficient moments-based approach was presented for computing key distortion figures of merit in radio frequency circuits from the harmonic balance equations, without the need to perform a harmonic balance simulation. In this paper, we show how the moments method can also be used to perform an efficient and accurate sensitivity analysis through the computation of the expansions of the moment vectors with respect to a circuit parameter, i.e., the multidimensional moments. We show that the sensitivities of key distortion figures of merit, including the 1 dB compression point and different intercept points, at all outputs in the circuit can be obtained with minimal additional computation cost to that of the original algorithm, thereby providing insight into the circuit performance.

Measuring the effects of nonlinear intermodulation distortion is one of the main requirements in the design of radio frequency circuits. The third-order intercept point (IP3) is one of the main figures of merit that is used to characterize this distortion and is expensive to compute due to the presence of multi-tone inputs. Recently, an efficient method for computing the third order intercept point, using moments analysis, was presented. However, this approach does not provide any sensitivity information. In this paper, we propose an efficient and robust method for computing the sensitivity of IP3 using adjoint moments with minimal additional computational cost.

Obtaining the value of the third order intercept point using traditional simulation techniques typically requires a nonlinear steady state analysis with multitone inputs, which is very computationally expensive. In this paper, a new method is presented for the computation of the third order intercept point. Using the proposed approach, the necessary Volterra kernels are computed directly from the harmonic balance equations. The only computation cost is that of solving a set of sparse linear equations. Furthermore, only one input tone is required in this case, which greatly reduces the size of the equations and thus the computation cost.

Intermodulation distortion is one of the key design requirements of Radio Frequency circuits. The standard approach for analyzing distortion using circuit simulators is to mimic measurement environments and compute the response due to a two-tone input. This considerably increases the CPU cost of the simulation because of the large number of variables resulting from the harmonics of these two tones and their intermodulation products. In this paper, we propose an analytical method for directly obtaining the intermodulation distortion from the Harmonic Balance equations with a only single-tone input, without the need to perform a Harmonic Balance simulation. The proposed method is shown to be significantly faster than traditional simulation based approaches.

Nonlinear distortion, typically defined using the third order intercept point (IP3), is one of the key figures of merit that are critical in the design of RF communication circuits. The calculation of IP3 is typically based on analytical approaches such as Volterra series which are very complex and difficult to apply to circuits of arbitrary complexity, or on simulation based methods which require multi-tone inputs and thus result in a very high CPU cost. In this paper a new method based on the computation of the circuit moments is proposed. The new approach uses the circuit moments in order to numerically compute the Volterra kernels. This automates the process of numerically obtaining such kernels for any circuit and results in an efficient approach for the computation of IP3