1.9 GHz range ultra-low-loss and steep cut-off double mode SAW filter for the Rx band in the PCS antenna duplexer

Inoue, S.; Tsutsumi, J.; Iwamoto, Y.; Matsukawa, Takashi; Miura, Mika; Satoh, Y.; Ueda, Masahiko; Ikata, O.

doi:10.1109/ultsym.2003.1293429

Cited by 19 publications

(5 citation statements)

References 3 publications

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“…Figure 7 shows the topology of the Band VIII duplexer, where the transmitting (Tx) filter is a pure ladder-type filter, while the receiving (Rx) filter is composed of resonators as well as a DMS. The inclusion of the DMS filter in the Rx filter is essential due to its superior out-of-band rejection and isolation, particularly on the lower side of frequency responses [29][30][31]. The NR Band VIII duplexer was fabricated using a high-Q TC-SAW process in Changzhou ChemSemi Corporation (Changzhou, China) [32].…”

Section: Design Of a Tc-saw Duplexermentioning

confidence: 99%

An Improved Method to Compute the Mutual Capacitance between Interdigital Transducers in Radio Frequency Surface Acoustic Wave Filters

Zou,

Yang,

Luo

et al. 2024

Micromachines

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This paper proposes an improved method to calculate the mutual capacitance between interdigital transducer (IDT) electrodes to enhance the accuracy of the traditional coupling-of-modes (COM) model, which is commonly used to simulate surface acoustic wave (SAW) filters and duplexers. In this method, the boundary element method (BEM) is adopted to obtain the capacitance per unit length in a layered medium, while the partial capacitance (PC) method is used to derive the effective relative permittivity of the multi-layered IDT. Numerical results from commercially available software are provided for comparison with the results calculated using the proposed method. The consistent results verify the validity and accuracy of this method, which also demonstrates significantly faster calculation speed compared to commercially available software. Precise electrical response prediction of a dual-mode SAW (DMS) filter can be achieved by applying this method to the COM model, and this ultra-fast calculation method can also be included in filter design optimization.

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Section: Design Of a Tc-saw Duplexermentioning

confidence: 99%

An Improved Method to Compute the Mutual Capacitance between Interdigital Transducers in Radio Frequency Surface Acoustic Wave Filters

Zou,

Yang,

Luo

et al. 2024

Micromachines

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“…1. Although 3-IDT and 5-IDT configurations [1], [11]- [13] are widely used in practice, their operation and design principles are basically the same with those of the 2-IDT one.…”

Section: Operation Of Conventional Dms Filtersmentioning

confidence: 99%

“…For their excellent performance, the pitch-modulated IDT and reflector already have been applied to the development of receiver (Rx) filters in the Personal Cellular System (PCS) Antenna duplexer [11].…”

Section: Introductionmentioning

confidence: 99%

Operation Mechanism of Double-Mode Surface Acoustic Wave Filters with Pitch-Modulated IDTs and Reflectors

Hashimoto

Omori

Yamaguchi

2007

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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One of the authors (KH) previously proposed pitch-modulated interdigital transducers (IDTs) and reflectors for developing low-loss and wideband longitudinally coupled double-mode SAW (DMS) filters. This paper discusses how a wide and flat passband is realized by applying the pitch-modulated IDTs and reflectors to DMS filters. It is shown that the pitch-modulated structure enables one to adjust the location of multiple resonance frequencies simultaneously by varying an effective reflective position with frequency. That is, the IDTs are pitch-modulated so that the outer portion has slightly larger pitch than the inside, and the pitch of the outermost reflectors is made largest. Accordingly, higher-order SAW resonances occur between the two pitch-modulated IDTs. The outer portion of each IDT acts as a reflector, and the inner portion is mainly responsible for SAW excitation. Lower-order SAW resonances occur between the two reflectors.

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“…Most of the duplexer structures are composed of ladder-type and double-mode SAW (DMS) filters. (12,13) The laddertype SAW filters are composed of numerous SAW resonators that are in serial and parallel arrangements and integrated on a single chip. They exhibit lower insertion losses and higher power capabilities than the DMS structure filters.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Characteristics of Dual-band Ladder-type Surface Acoustic Wave for High-power Durability Duplexer

Hsu

Chen

et al. 2019

Sensors and Materials

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A circuit investigation of dual-band surface acoustic wave (SAW) filters of the ladder type is proposed. The designed filter exhibits a broader bandwidth and a sharper cutoff frequency than the conventional filter composed of the ladder and double-mode SAW (DMS) types. The SAW filters have been widely applied to the antenna duplexer given the progress in mobile communication technology. Furthermore, the SAW filters can be constructed into a wireless sensor system in combination with a SAW sensor. We demonstrate how simulations of laddertype SAW filters based on the 48°YX-LiTaO 3 are used to achieve a convenient design of the SAW band-pass filter for a high-power and wireless sensor system. These filters demonstrate the lowest insertion loss, the largest bandwidth, the optimal power durability, and a thirdorder intercept point compared with the interdigital transducer (IDT) and DMS. A simulation of a SAW resonator using the advanced design system (ADS) is performed with the lumped elements. The first passband that is applied to the Tx duplexer is in the range of 823-855 MHz, and the second passband applied to the Rx duplexer is from 867 to 898 MHz. The frequency characteristics of the ladder-type duplexer possess minimum insertion losses of 1.14 dB in the first passband and 0.54 dB in the second passband, which are similar to those of the DMS duplexer. The isolation performance between Tx and Rx is 42.22 dB at 823-898 MHz, which is less than that of the DMS duplexer. The design of the appropriate SAW band pass filter will be simplified through a precise simulation. Furthermore, the dual-band structure with a laddertype SAW can be expected to endure higher power and have a better isolation performance than conventional DMS structures.

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1.9 GHz range ultra-low-loss and steep cut-off double mode SAW filter for the Rx band in the PCS antenna duplexer

Cited by 19 publications

References 3 publications

An Improved Method to Compute the Mutual Capacitance between Interdigital Transducers in Radio Frequency Surface Acoustic Wave Filters

An Improved Method to Compute the Mutual Capacitance between Interdigital Transducers in Radio Frequency Surface Acoustic Wave Filters

Operation Mechanism of Double-Mode Surface Acoustic Wave Filters with Pitch-Modulated IDTs and Reflectors

Investigation of Characteristics of Dual-band Ladder-type Surface Acoustic Wave for High-power Durability Duplexer

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