Design of Patterned Transcendental Metamaterial Cover Structures for Crosstalk Reduction in FBAR Parallel Feed Lines

With the rapid development of modern high-speed circuit technology, electronic devices have the properties of high data transmission rates, steeper edge changing rates, and large-scale integration which can lead to increased crosstalk challenges in high-speed planar circuit designs. Severe crosstalk problems can result in disrupted data transmission and increase bit error rates (BER). Therefore, in order to reduce crosstalk problems and increase signal transmission quality, this paper studies the far-end crosstalk (FEXT) suppression of film bulk acoustic resonator (FBAR) parallel feed lines in high-speed data rate transmission. First, the theory of FBAR crosstalk is analyzed, and the influential factors such as line spacing, trace coupling length on crosstalk in FBAR feedlines are analyzed from the perspectives of frequency domain and time domain. Then, several structures based on geometric fractal substrate covers are proposed. The proposed structures utilize modern mathematical transcendental planar geometry such as modified Hilbert fractal, Minkowski fractal and von Koch fractal metamaterial covers. By adding these structures, the distributed capacitance of the line is increased to neutralize the magnetic coupling between the lines, thus reducing the FEXT both in frequency and time domains. The optimization is both performed through full-wave simulation and circuit simulation. As the results show that, in the frequency domain, the FEXT can be maximumly reduced about 26 dB from 0.1 GHz to 16 GHz. For signal transmitting verification, the lines are fed with DDR5 (the fifth-generation double data rate) signals, and the FEXT can be reduced over 21 mV, which corresponds to over 95% of the FEXT reduction in the time domain. The proposed structure can be applied in modern high speed planar circuits and wireless communication systems.