Stability of LTCC substrates in high frequency area after accelerated aging tests

Aim of this paper is to investigate influence of accelerated ageing on dielectric properties of Low Temperature Co-fired Ceramic (LTCC) substrates with microstrip structure. According to the previous work of Pietrikova et. al (2013), narrow-band notch filter from 2.4 GHz to 2.5 GHz, for minimalizing impact of Wi-Fi signal on UWB radar systems, was designed and fabricated using two different LTCC substrates´ types (DuPont GreenTape 951 and DuPont GreenTape 9K7). All filters were exposed to temperature loads, measured before and after each part of accelerated aging tests. Two types of aging test were chosen: “HTOL” (High Temperature Operation Life) and temperature cycling test. LTCC substrates´ stability were derived from the changes in frequency domain characteristic obtained from measurements by Vector Network Analyser (VNA) up to 12 GHz. Results shown that there is no significant difference in stability of DuPont GreenTape 951 and DuPont GreenTape 9K7 loaded by HF and thermal stress.