The most popular surface wave components for mobil

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In recent years, many new functions have been added, such as camera, music player, GPS (Global Positioning System), ground digital video receiving, Bluetooth, etc., showing amazing multi-functional applications. At the same time, from the popularity of ultra-thin models, it can be seen that in addition to functions, consumers' requirements for appearance design are becoming more and more diversified. In the process of miniaturization, multifunction and diversification, the rapid miniaturization and high performance of electronic components have played an important role in promoting the development of. After receiving the radio wave, the antenna needs to screen out the necessary parts and realize stable communication. Therefore, the high-frequency filter is a necessary electronic component in the, and the surface wave filter has become one of the evolutionary electronic components because of its small size and high selectivity

The saw: surface acoustic wave components used in

have various uses, such as transceiver duplexer for CDMA communication, interstage filter for transceiver, top filter for GSM communication, GPS, Wi Fi, Bluetooth, ground digital video and other application functions that contribute to the multi-function of. Murata production Institute is committed to developing new products for various purposes. The following will introduce the latest trends of surface wave components

transceiver duplexer

cdma communication requires a duplexer that can receive and transmit at the same time. The transceiver duplexer is a high-frequency element that enables the TX filter and Rx filter to share the same antenna through a branch circuit. The most important performance of the transceiver duplexer is to ensure the isolation between TX and Rx (indicating how far the signals between TX and Rx pins can be isolated). In practical use, in addition to providing sufficient isolation, the next important performance is to reduce the loss of TX and Rx filters respectively

for example, figure 1 shows the transmission characteristics and isolation of band5 (800MHz) transceiver duplexer (product size 2.5 2.0 0 0.6mm). The general isolation and filterability loss are mutually restricted. However, this product can achieve a high isolation of 60dB for TX frequency band and maintain RX loss at 1.8dB

Figure 1: electrical characteristics of W-CDMA band5 (800MHz) transceiver duplexer Product Name: sayev836mac0f00

the second example is the characteristics of Band1 (2GHz) transceiver duplexer (product size in Figure 2. The special design technology is introduced into Band1 (2GHz), which is difficult to achieve low loss by surface wave. While obtaining the isolation required for practical use, it can also achieve outstanding low loss characteristics such as TX loss of 1.4db and Rx loss of 1.8dB. For a long time, the dielectric transceiver duplexer once occupied the mainstream position in Band1 (2GHz) band, and the current surface wave has achieved no less than its loss value. Therefore, the surface wave transceiver duplexer has become the mainstream instead of the dielectric transceiver duplexer

Figure 2: electrical characteristics of W-CDMA Band1 (2GHz) transceiver duplexer Product Name: sayzy1g95ea0b00

Murata Manufacturing Institute uses high isolation detection and low loss design technology for finished and semi-finished products, carefully studies surface wave transceiver duplexers used in many high frequency bands (bands) specified in 3GPP (Third Generation Partnership Program), and actively responds to the new generation of high-speed communication bands used in the future. In the future development, Murata production Institute will actively study duplexers with balanced output RX pins that meet the market demand while developing smaller transceiver duplexers


the surface wave filter used in the high-frequency wireless communication circuit of includes inter stage filter for CDMA transceiver and top filter for GSM. Murata's filter not only has the electrical characteristics of low loss and high rejection, but also has a rich commodity line composed of small and thin product sizes, which can meet the needs of various circuit designs. For example, in the high-frequency wireless communication circuit with multi band development, in order to reduce the mounting area on the circuit substrate, the single filter (product size 1.35 1.05 0.5mm) of the two bands is combined into one to produce a double filter (product size 1.8 1.35 0.5mm). In addition, special technologies are used to manufacture many unique products, such as 1in4out products that combine the input of the double-layer filter into one, and 2in2out products that combine the output of the balancer into one. The switch (SW) originally used for frequency division can be saved by sharing the input terminals. At the same time, sharing the balanced output can reduce the number of ports of the high-frequency IC connected to the filter (Fig. 3). In the design of surface wave filter, the impedance and phase are adjusted so that the differential ports can be shared. These filters can contribute to the simplification of peripheral circuits and the miniaturization of the whole circuit in the high-frequency wireless circuits with multi band development. In the future, Murata production Institute will continue to devote itself to the research and development of single filter and double filter products that are more miniaturized and high-performance, and have the common functions of input and output

Figure 3: example of input/output port structure of double-layer filter various applications of the filter

gps, Bluetooth and Wi Fi that realize short-range wireless communication, and various models that can receive ground digital video, have become increasingly versatile representatives. In order to equip these application functions on a terminal at the same time, it is necessary to first evaluate the mutual interference between the communication transceiver signals and the communication signals of each application function. For this reason, it is necessary to have a filter that can eliminate noise while not affecting the necessary frequency band of each application function. The signal used in the transceiver communication has multiple frequency bands, and the frequency band of the transceiver is close to the necessary frequency band of various application functions, so the filter is required to have steep suppression characteristics. For the transceiver frequency far away from the effective frequency band, the depth:> 860 mm; That is to say, a relatively large attenuation and suppression system is required. To meet these needs, Murata Manufacturing Institute continuously manufactures and develops surface wave filters for various application functions. Bayer materials technology said that the company is contacting the local Labor Committee and labor union

take the electrical characteristics of the top filter for Wi Fi (product size 1.35 1.05 0.5mm) in Figure 4 as an example. Band1 (2GHz) receiving band exists in the low-frequency area of the Wi Fi band (2.5GHz). In order to prevent mutual interference between the two, band2 receiving band needs to have large attenuation characteristics. Therefore, it is necessary to use the high attenuation design method commonly used in interstage filters. In order to make the top filter for Wi Fi receive and transmit at the same time, the filter must bear high transmission power, but the traditional design method is difficult to achieve. Murata production Institute has introduced a special design technology of high power endurance and high attenuation, which not only realizes high power endurance (24dbm), but also has outstanding low loss and high attenuation characteristics. In the future, Murata will further develop this design technology and research and manufacture top filters for MIMO used in high-speed communication

figure 4:electrical characteristics of Wi Fi to repay the society with better products and services Product Name: safea2g45ac0f00

future outlook

as a future outlook, the following three points are mainly exemplified: (1) in order to further miniaturize and simplify the design, Murata will also be committed to modular research -- packaging high-frequency passive components into a module. Among them, for the needs of die-casting mold and thinness, Murata Manufacturing Institute has developed new components using the bpaw: buried propagating layer acoustic wave technology. In the future, while continuing to develop saw components, bpaw components will also be developed to develop more products suitable for die-casting die modules and discrete circuits. (2) With the gradual improvement of the performance of high-frequency IC and IC peripheral high-frequency components, there is a new demand for balanced output transceiver duplexer at the receiving end. Murata Manufacturing Institute extends the design technology accumulated so far for the balanced filter used to design interstage filter to the balanced output transceiver diplexer, and further develops products that can cope with various frequency bands. (3) Nowadays, the technology is developing nonstop. It can be predicted that with the current third generation mobile (3G) as the starting point and the third generation mobile (3.9G) pursuing higher speed as the transition period in the future, the technology will gradually enter the era of the fourth generation mobile (4G). In the process of developing to 3.9G and 4G, the frequency band used will be higher than now. In this regard, Murata production Institute will focus on the research of surface wave components as an important technical topic in the future

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