A display apparatus includes a first insulating substrate including a display area in which a first opening is formed, as well as a non-display area. A microwave frequency band stub resonance booster circuit characterized by boosting the amplitude of an RF signal in a passive operation by resonating in series a 0. The input device may be a sensor capable of measuring a condition relating to the training. Prior to triggering an alarm, regions identified as indicative of fire are compared with the user-defined acceptable regions.