摘要:
A 3-frequency branching circuit in the past could not be used for a system wherein a TDMA method such as GSM and DCS and a W-CDMA method such as UMTS are mixed. The 3-frequency branching circuit equipped with branching means having first and second internal terminals, an antenna terminal of connecting to an antenna, a low-pass filter connected between the first internal terminal and the antenna terminal, and a high-pass filter connected between the second internal terminal and the antenna terminal, a switching circuit of switching between GSM TX and GSM RX, a switching circuit of switching between DCS TX, DCS RX and a third internal terminal, and a duplexer connected to the third internal terminal.
摘要:
A laminated filter includes: a first dielectric layer having a first shield electrode on one principal plane; a second dielectric layer having resonator electrodes on one principal plane; a third dielectric layer having a coupling electrode provided facing part of the above-described resonator electrodes; a fourth dielectric layer having a second shield electrode on one principal plane; a fifth dielectric layer whose at least one principal plane is exposed outside; and a grounding electrode provided on the other principal plane of the above-described dielectric layer and/or the above-described one principal plane of the above-described fifth dielectric layer, and the above-described first grounding electrode and the above-described first shield electrode are electrically connected through a via hole provided in the above-described first dielectric layer.
摘要:
A filter having an unbalanced terminal, a first stripline resonator of which one end is connected to the unbalanced terminal, a second stripline resonator placed to be electromagnetically coupled to the first stripline resonator, and balanced terminals of which both ends are connected to the second stripline resonator, wherein the first stripline resonator and the second stripline resonator are connected by at least one impedance element, and the second stripline resonator is a ½ wavelength resonator substantially having ½ the length of a wavelength of a resonance frequency.
摘要:
Interdigital transducers (IDT electrodes), reflectors, etc., are formed on a piezoelectric substrate. An unbalanced input/output terminal is connected to a first input/output terminal. A first inductor is connected between a first terminal, which is one of the balanced input/output terminals, and a second terminal, which is the other of the balanced input/output terminals. Further, a second inductor is connected between the first terminal in the balanced input/output terminals and a second input/output terminal, and the second terminal in the balanced input/output terminals is connected to a third input/output terminal.
摘要:
A surface acoustic wave filter has a piezoelectric substrate and at least two interdigital transducer electrodes on the piezoelectric substrate, wherein at least one of the interdigital transducer electrodes includes a unidirectional electrode and bidirectional electrode, and the length &lgr;d of a basic cell of the unidirectional electrode is longer than the length &lgr;s of a basic cell of the bidirectional electrode.
摘要:
Disclosed is a surface acoustic wave filter on a piezoelectric substrate. The filter includes at least two surface acoustic wave resonators that each has a reflector electrode on both sides of an IDT electrode as an inter-digital transducer electrode. At least two of the resonators are disposed on a piezoelectric substrate in positions near each other so that the propagation direction of surface acoustic waves are in parallel to make an acoustic coupling. In an embodiment, the acoustic coupling is a direct coupling. The IDT electrode has a plurality of electrode fingers connected so as not to cancel respective electric charges. The IDT electrode is constituted by at least three divisional IDT electrodes. A pair of the electrode fingers can have a reverse phase relation with respect to each other. Also, in a multi-stage surface acoustic wave filter, the electrode fingers can be included in an upper IDT electrode of a top stage of the filter, and in a lower IDT electrode of a bottom stage of such filter.
摘要:
A surface acoustic wave resonator is constituted by an IDT electrode and reflector electrodes disposed on both sides thereof, on a piezoelectric substrate. Two of said surface acoustic wave resonators are disposed nearby so that the propagation directions of the respective surface acoustic waves are in parallel to each other to make acoustic couple to constitute a surface acoustic wave filter having plural exciting modes with different propagation frequencies. The bus bar electrodes of each of two IDT electrodes are electrically separated from each other, and the leading out electrodes led out from at least two spots on those bus bar electrodes are electrically connected to each other, by which one side of the balanced input and output terminal. As a result, the electrode resistance of the IDT electrode is alleviated to make the insertion loss less.
摘要:
A surface acoustic wave resonator is constituted by an IDT electrode and reflector electrodes disposed on both sides thereof, on a piezoelectric substrate. Two of said surface acoustic wave resonators are disposed nearby so that the propagation directions of the respective surface acoustic waves are in parallel to each other to make acoustic couple to constitute a surface acoustic wave filter having plural exciting modes with different propagation frequencies. The bus bar electrodes of each of two IDT electrodes are electrically separated from each other, and the leading out electrodes led out from at least two spots on those bus bar electrodes are electrically connected to each other, by which one side of the balanced input and output terminal. As a result, the electrode resistance of the IDT electrode is alleviated to make the insertion loss less.
摘要:
An inter-digital transducer has a piezoelectric substrate; and an IDT (inter-digital transducer) electrode having a pair of upper bus bar electrode and lower bus bar electrode placed facing each other on the piezoelectric substrate and a plurality of electrode fingers placed on the piezoelectric substrate each being led out from either the upper bus bar electrode or the lower bus bar electrode toward the other bus bar electrode, wherein the IDT electrode is constructed of a plurality of divisional IDT electrodes and connected to a balanced type terminal.
摘要:
An antenna duplexer has a receiving filter having a surface acoustic wave device; a transmitting filter having a dielectric resonator; and a matching circuit for matching the receiving filter and the transmitting filter with an antenna respectively, wherein the transmitting filter, receiving filter, and matching circuit are integrated with each other.