Liquid crystalline polymer based RF/wireless components for multi-band applications

This paper presents for the first time the design, implementation, measurements, reliability data and integration of multiple RF components such as filters, baluns, diplexers, and a combination of the above on liquid crystalline polymer (LCP) based substrates for communication standards such as 802.11 a/b/g, LMDS/MMDS, satellite/digital TV, UWB, cellular and Bluetooth type applications. These components and process technologies are being targeted as a cost-effective high-performance, miniaturized alternative to the primary technologies of choice for multi-band RF/wireless applications, namely, low-temperature co-fired ceramic (LTCC), multi-layer ceramic (MLC) and ceramic monoblock technologies. The first examples of this platform substrate technology are very compact 12 mm³ fully packaged SMT front-end filters with center frequencies of 2.45, 5.25 and 5.775 GHz. One embodiment of the filter at 2.45 GHz, which is well suited for 802.11 b/g and Bluetooth type applications, provides a passband of 100 MHz with maximum inband insertion loss less than 1.7 dB at 25°C, greater than 25 dB attenuation at 2700-2800 MHz, greater than 10 dB attenuation below 2.2 GHz, greater than 20 dB rejection at the second and third harmonic and inband VSWR less than 1.5 matched to 50 ohms at the input and output.