Small Loop Antenna System Design for Radio Direction Finding

In this literature, a low-cost small loop antenna is developed for radio direction finding. It consists of two coupled rectangular counter-wiring loop antennas. A signal-processing circuit is developed also for demodulated outputs. A single rectangular loop antenna is discussed first for illustrating the receiving characteristics and then the proposed two coupled rectangular counter-wiring loop antennas are designed for radio direction finding. Measurements give a large linear detecting range. It is ready for Omni-directional application using another two coupled loop antennas and can be used as a tracking control device.

Dynamic FPAA-based Mixed-Signal Processing Circuit for Thin-Film CdTe/Lead-Free Perovskite Photodetectors

New photodetector structure combining thinned CdTe film with lead-free perovskite photoelectric film was produced and investigated. This setting of the CdTe thickness results in photodetector parameters’ competitiveness to the state-of-the-art in the field of advanced photoelectric materials. The device shows a promising sensitivity of ~40 μA/W, maximum responsivity of 10.6 mA/W at 460 nm, equal rise and fall times of 30 ms, and high linearity (maximum linearization error is less than 0.6 %). However, the optoelectronic performance of CdTe/lead-free perovskite structures integrated with signal processing circuit remains unexplored. For this purpose, Field Programmable Analogue Array (FPAA)-based mixed-signal processing circuit is developed for pulse width modulated electrical signal with duty cycle controlled by the illumination degree of the detecting photoelement. This novel approach guarantees a smooth change of the electrical output at a smooth change of the input illumination between the light and dark switching states and can be practically applied as a precise position detector of moving objects. The paper represents a synergistic connection between microelectronics, electronics, and signal technology.