Microwave Analog Real-Time Spectrum Analyzer (RTSA) Based on the Spectral–Spatial Decomposition Property of Leaky-Wave Structures

Efficient time-domain analysis of highly dispersive linear and non-linear metamaterial waveguide and antenna structures operated in the impulse-regime

“…Based on this spectral-spatial decomposition, a novel real-time spectrogram analyzer (RTSA) has recently been proposed [15,16]. The idea is to characterize, both in frequency and time, an unknown UWB input signal.…”

“…Once the current distribution along the antenna is known for all frequencies in the fast-wave region, the corresponding far-field radiation as a function of time is obtained using standard Fourier transforms [22]. This far-field radiation is finally given by 16) where  r is the observation point in free-space, z 0 and z ℓ are the initial and last points of the physical structure (with ℓ =z ℓ −z 0 ), z ' is an arbitrary point along the CRLH line and R=| r −z '| .…”

“…The first step to model the RTSA is to perform the calibration of the system. This is necessary to compensate for the different power levels received at each probe [15,16], due to the directivity variation with frequency [3]. For the calibration, a narrow-band signal is modulated to the different fast-wave frequencies [following Eq.…”

“…In this paper, we propose a numerical method [13] to study: (a) impulse-regime phenomenology of non-linear metamaterial composite right/left-handed (CRLH) transmission lines (TL) [14], and (b) radiative impulse-regime properties of CRLH leaky-wave antennas (LWAs) [3] and its application to the characterization of a realtime spectrogram analyzer (RTSA) [15,16].…”

“…In the case (b), the radiation formulation presented in [13] has been employed to characterize a real-time spectrogram analyzer (RTSA) system [15,16], based on CRLH leaky-wave antennas (LWAs). A novel power calibration method has been proposed to accurately characterize unknown signals, considering the directivity variation with frequency.…”