Transmission characteristics of an AC/coaxial adapter that is used for calibration of an AMN had been evaluated up to 30 MHz, which is the upper limit of frequency in the use of conventional AMNs. However, the new type AMNs for using over 30 MHz has been developed, thus the transmission characteristics of the adapter beyond 30 MHz should be evaluated. In this paper, a circuit model of the AC/coaxial adapter is developed in order to obtain easily its transmission characteristics up to 1 GHz. The calculated characteristics using the developed circuit model agreed well with that of simulated by using a numerical electromagnetic analysis.
We studied a novel nonlinear compensation scheme using digital signal processing based on a neural network (NN). Distortion of 16QAM signals caused by self-phase modulation (SPM) was compensated for by using a three-layer NN without feedback loops. In the scheme, the input layer of the NN has feedforward tapped delay lines. Input signals of I and Q components of the 16QAM signals are fed into the delay lines. The compensated 16QAM signals of the I and Q components are outputted by two neurons in the output layer of the NN. BER and EVM performance was investigated by numerical simulations, and the EVM was improved by more than 20% by the compensation.
A mechanical beam scanning dipole array antenna coupled to a meander two-wire parallel transmission line is proposed. A meander transmission line is introduced to the proposed antenna in order to suppress its grating lobe without using lumped element inductors. Numerical simulation demonstrates that the proposed antenna is capable of continuous beam scanning ranging from 2°(@ϕ = 0) to 42°(@ϕ = 180°) without grating lobe due to the meander transmission line.
The capacity of binary input additive white Gaussian noise (BI-AWGN) channel has no closed-form solution due to the complicated numerical integrations involved. In this letter, a simple upper bound to evaluate the capacity of BI-AWGN channel is presented. In addition, through the moment generating function (MGF) of fading channel gain, the upper bounds of fading channels are derived by averaging the proposed bound with respect to the probability density function (pdf) of fading gain.
The waveform algorithm for active target classification or identification based on spectral variance has been studied in various pieces of literature. The algorithm was extended for widely-separated MIMO Radar system to take advantage of spatial diversity gain by Bae et al. However, the MIMO waveform can be improved further by considering multiple objective functions from the multiple target paths. In this letter, we optimize the MIMO waveform for target identification system by maximizing the multiple objective functions. We show simulation results to compare the proposed algorithm to other MIMO waveform design methods.