US 12,074,587 B2
Single substrate multiplexer
Florian Habel, Munich (DE); Thomas Bauer, Munich (DE); Peter Hagn, Finsing (DE); and Thomas Dengler, Munich (DE)
Assigned to RF360 Singapore Pte. Ltd., Singapore (SG)
Appl. No. 17/597,465
Filed by RF360 SINGAPORE PTE. LTD., Republic Plaza (SG)
PCT Filed Jul. 9, 2020, PCT No. PCT/EP2020/069415
§ 371(c)(1), (2) Date Jan. 6, 2022,
PCT Pub. No. WO2021/009008, PCT Pub. Date Jan. 21, 2021.
Claims priority of application No. 10 2019 119 239.0 (DE), filed on Jul. 16, 2019.
Prior Publication US 2022/0173723 A1, Jun. 2, 2022
Int. Cl. H03H 9/72 (2006.01); H03H 9/02 (2006.01); H03H 9/05 (2006.01); H03H 9/25 (2006.01); H03H 9/56 (2006.01)
CPC H03H 9/725 (2013.01) [H03H 9/02559 (2013.01); H03H 9/058 (2013.01); H03H 9/25 (2013.01); H03H 9/568 (2013.01); H03H 9/02834 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A multiplexer, comprising:
a monolithic stack comprising:
a carrier substrate;
a piezoelectric layer above the carrier substrate having a main surface; and
at least one dielectric layer arranged between the piezoelectric layer and the carrier substrate;
a metallization on top of the main surface comprising:
an antenna terminal for connection with an antenna;
three signal pads;
a trap-rich layer (TRL) provided between the carrier substrate and the piezoelectric layer, wherein the trap-rich layer comprises a polycrystalline silicon layer;
three surface acoustic wave (SAW) filter circuits connected in parallel between the antenna terminal and a respective signal pad, wherein each of the three SAW filter circuits comprises a corresponding series signal line and a number of SAW resonators connected in series with or parallel to the corresponding series signal line; and
a package providing a cavity on top of the monolithic stack, wherein the three SAW filter circuits are enclosed in the cavity that is formed between the main surface of the piezoelectric layer and a lid and/or a cover.