A Hybrid Transmission-Line/SAW-Resonator Analog Signal-Interference Dual-Band Bandpass Filter

Highly coupled leaky surface acoustic wave on hetero acoustic layer structures based on ScAlN thin films with a c-axis tilt angle

“…With the arrival of the 5G era, acoustic wave-filtering components have more stringent requirements, such as for a higher electromechanical coupling coefficient (K 2 ), higher frequencies, and a higher Q factor or admittance ratio, etc. [1][2][3][4][5][6][7][8] For SAW devices, those characteristics mainly depend on their piezoelectric substrates.…”

Development and Application of SAW Filter

“…For example, based on conventional acoustic wave resonator filter design techniques (lattice and ladder-type SAW filter design), the achievable 3 dB fractional bandwidth (FBW) is only 0.4 and 0.8 times that of the SAW resonator k 2 t. In 2020, Ting Cai, put a lot of effort into increasing the bandwidth of filters based on SAW resonators, to achieve bandwidth that is not constrained by the electromechanical coupling coefficients they employ. A novel dual narrowband BPF design is based on a hybrid resonator of transmission line TFS and high-Q SAW, the achievable bandwidth of the filter is not constrained by the electromechanical coupling coefficients it adopts, the SAW resonator and its transmission characteristics, the filter can be flexible control [ 21 ]. In the same year, Runqi Zhang, proposed a hybrid low-cost bandpass filter.…”

Synthesis Design of Wideband Bandpass Filter With High Selectivity and Harmonic Suppression

“…The BPFs with high selectivity and extended upper stopband are urgently needed in multilayer microwave integrated circuits. They can significantly enhance the electromagnetic compatibility and decrease delay time of signal transmission [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. Therefore, they have always attracted much attention and are the focus of research in both academic and industrial fields.…”

“…One of the most popular methods is to exploit transversal signal-interference technique, which the input signal is divided into two propagation paths with different phase and magnitude responses. The open/shorted coupled lines [1], a shunted open-ended stub with resistors at terminal nodes [2] [5], composite transmission lines combining surfaceacoustic-wave (SAW) resonators [3], and RF switches dynamically connected to transmission lines [4] are utilized to achieve transversal interference. However, the practical applications will be limited due to suffering from undesired spurious harmonics seriously.…”

“…On the one hand, the position distribution of in-band six poles can be calculated accurately based on odd-/even-mode circuit topology, which the design principle is clearer and more straightforward compared with traditional parameter sweep analysis [6] [8]. On the other hand, it is very different from conventional time-consuming coupling topology optimization approach [3][4][5][6][7], most of the circuit parameters can be explicitly determined in terms of prescribed specifications, which improve design efficiency remarkably. Moreover, in order to investigate operating mechanism of harmonic suppression in depth, the positions of additional TZs can be accurately derived from the characteristic function formula of proposed BPF, which not only broaden the upper stopband significantly but also enhance the harmonic rejection level greatly as well.…”