Low temperature cofired ceramic (LTCC)-process-based duplexer with novel structure

Abstract

The invention discloses a duplexer, which is applied to global system for mobile communication (GSM) / data communication system (DCS) frequency bands and realized by a low temperature cofired ceramic (LTCC) technology. The duplexer comprises a high-pass filter connected with a common port and a low-pass filter connected with the common port. A low temperature series resonator which attenuates low frequency component is connected in parallel between the common port and the high-pass filter, two capacitors with equal capacitance are connected in series between the common port and the high-pass filter, and the high-pass filter forms a maximal transmission coefficient point in a high frequency pass band; and a series resonator which attenuates high frequency components is connected in parallel between the common port and the low-pass filter, and a parallel resonator which attenuates higher frequency components is connected in series between the common port and the low-pass filter.

Description

technical field [0001] This product relates to a duplexer for lumped elements in the communication field, in particular to a lumped element duplexer processed by multi-layer LTCC technology. Background technique [0002] With the continuous development and improvement of the mobile communication system, the requirements for mobile communication equipment are getting higher and higher, and the mobile phone system is continuously promoted to be miniaturized and multi-mode (compatible with GSM900 / DCS1800, PCS, IS- 95 and 3G systems) and the direction of high performance, which promotes the development of duplexers in the direction of low cost, miniaturization, and high frequency band. [0003] In a mobile communication system, the reception and transmission of wireless signals need to pass through the antenna. If one antenna is allocated to the receiver and the transmitter, not only the cost and volume will be increased, but also the signals transmitted by the antennas will in...

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Problems solved by technology

[0004] After searching the literature of the prior art, it is found that Chinese patent 1661912A proposes a lumped prototype of a duplexer that can suppress the loss of multiple frequency band signals transmitted along the side of the high-pass filter and the side of the low-pass filter respectively. From its lumped It can be seen from the prototype that four resonators and two capacitors and inductors were introduced in the patent, which caused too many components, which also caused excessive interference between components when converted into an actual production and processing model, resulting in serious It affects the performance of the duplexer, and such too many components are not conducive to the miniaturization of the duplexer, and from the simulation results given later, it can be seen that although the duplexer can meet the requirements of high isolation, the insertion loss is relatively relatively large, which causes this lumped prototype to not be widely used in practice, and can only provide a theoretical reference; in addition, US Patent 0058063 uses many ground planes to separate circuit components, although this is effective It blocks the mutual coupling and parasitic effects between circuit components, but on the other hand, it also increases the area of ​​the circuit board, which is undoubtedly unable to meet the requirements for miniaturization.

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