A Semi-Analytical Approach for Performance Evaluation of RTD-Based Oscillators

Abstract

In this paper, it is presented a comprehensive analysis of three optoelectronic oscillators circuits based on resonanttunneling diodes (RTD) for promising applications in terahertz frequency (THz) range. For all cases, it is investigated how each of these RTD devices performs under a wide range of the direct current (DC) voltages within the negative differential resistance region (NDR). The mathematical formalism developed here accounts for the effect of bias applied on the parameters of the reactive elements that composed the oscillators' small signal model. In this context, new expressions for evaluating the width of the depletion region of the devices are derived. Such mathematical formalism allows to make the performance analysis straightforward and show a close agreement to the device characterizations presented in the literature. Results pave the way for these RTD-based oscillators as potential candidates for Radio-over-Fiber (RoF) transmission, where higher operation frequencies will be major network requirements.

Performance Analysis of a THz Proximity Wireless Communication Based on RTD

“…The idea is to check how the width of the depletion region and, consequently, the negative differential region (NRD) of the I-V characteristics depends on such a fitting parameter and distinct values on the input voltage. It is important to assert that this proposed approach shows a close agreement to the several device characterizations presented in the literature and the interested readers should refer to [5] for further details. Now, the overall description of the transmitter can be achieved dealing with the effect of the transmitting antenna's coupling into the RTD device.…”

“…where ߝ ௗ is permittivity, ‫ݍ‬ is the electron charge, the ܰ and ܰ ௗ are the acceptor and donor concentrations in the collector region, respectively, ܸ is the input voltage and ‫ܯ‬ is an empiric factor estimated from the characterization of the devices. Full details on the proposed mathematical framework are available in [5]. After establishing the oscillating THz wave, the next step is to guide the THz beam radiated from the antenna of the oscillator circuit through the hemispherical lens.…”

“…Fortunately, all these requirements can be fully satisfied by one of the most prominent electronic devices available, namely resonant tunneling diode (RTD). Oscillators based on RTD is known to have the highest maximum oscillation frequency at room temperature of the inherent negative differential conductance (NDC) due to the resonant tunneling among the electronic devices [4], [5].…”

Performance Analysis of a Nanocolumn-RTD VCO for Emerging THz Wireless Applications

“…(2), L w is the length of the quantum-well, L b is the length of the barriers, ε w , ε b , and ε dep are the dieletric permittivities of the quantum-well, barriers and depletion region. The width of the depletion region is calculated using the analytical expression presented in our previous work [14] L…”

“…where q is the electronic charge, N a and N d are the densities of acceptors and donors, respectively, and M = 0.6673 (fitting factor), the validation of Eq. (4) was developed in [14]. Now, τ RT D is expressed as [13]…”