A transceiver for use in an ultrasound system is provided. , which satisfies the following expressions and :Re450<Re550<Re650\u2003\u2003Rth550<Re550\u2003\u2003. Further, by providing a supporting portion for the base substrate between the depression portions of the tray, a contact area between the tray and the base substrate is reduced. Sensor fittings are threadably engaged with the ports, and to support the threadable engagement, the wall of the coupling through which the ports are formed has a thickness of at least around one-half inch. Therefore, a fast processing time in writing and a large conduction current in reading are catered for.