Abstract
This paper presents a new wireless sensor structure based on a substrate integrated circular waveguide (SICW) for the temperature test in harsh environments. The sensor substrate material is 99% alumina ceramic, and the SICW structure is composed of upper and lower metal plates and a series of metal cylindrical sidewall vias. A rectangular aperture antenna integrated on the surface of the SICW resonator is used for electromagnetic wave transmission between the sensor and the external antenna. The resonant frequency of the temperature sensor decreases when the temperature increases, because the relative permittivity of the alumina ceramic increases with temperature. The temperature sensor presented in this paper was tested four times at a range of 30–1200 °C, and a broad band coplanar waveguide (CPW)-fed antenna was used as an interrogation antenna during the test process. The resonant frequency changed from 2.371 to 2.141 GHz as the temperature varied from 30 to 1200 °C, leading to a sensitivity of 0.197 MHz/°C. The quality factor of the sensor changed from 3444.6 to 35.028 when the temperature varied from 30 to 1000 °C.
Highlights
As a basic physical parameter, temperature plays an important role in the aerospace and automotive industries, mine operations and other industries
In [7], a temperature sensor based on an LC resonance circuit has been successfully tested at 900 ◦ C, which was fabricated based on high-temperature co-firing ceramic (HTCC)
Compared with the LC-based sensor, the substrate integrated waveguide (SIW) structure sensor can work at a microwave frequency band with a small dimension, while the LC sensor works at a lower frequency band in the 50–500 MHz range, and the SIW sensor is more sensitivity than the LC temperature sensors in [6,7]
Summary
As a basic physical parameter, temperature plays an important role in the aerospace and automotive industries, mine operations and other industries. In [7], a temperature sensor based on an LC resonance circuit has been successfully tested at 900 ◦ C, which was fabricated based on high-temperature co-firing ceramic (HTCC). This type of sensor cannot be used near metal surfaces because the magnetic field will be absorbed by the metal surface. In [19], a high-Q and miniaturized complementary split ring resonator (CSRR)-loaded substrate integrated waveguide (SIW) microwave sensor for the detection of cracks in metallic materials was presented.
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