High-linearity frequency mixer in radio frequency identification

A high linearity, radio frequency identification technology, applied in electrical components, modulation transfer, demodulation and other directions, can solve problems such as linearity deterioration, and achieve the effect of increasing conversion gain and improving the ability to handle large signals

CN102545786AInactive Publication Date: 2012-07-04SHANGHAI HUAHONG INTEGRATED CIRCUIT
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2012-07-04
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a high-linearity frequency mixer in radio frequency identification. The high-linearity frequency mixer comprises a load circuit, a switching circuit and a transconductance circuit, wherein the switching circuit is connected with the load circuit, and the joint of the switching circuit and the load circuit is provided with a signal output end; the switching circuit comprises a first current path; the transconductance circuit comprises two input transconductance pipes which are connected in parallel; each transconductance pipe is connected to the first current path; the signal input end of each input transconductance pipe is respectively connected with a bias resistor, and the bias resistor of each input transconductance pipe is respectively connected with a bias voltage; and the signal input end of each transconductance pipe is further respectively connected with an input blocking capacitor, and each input blocking capacitor is connected with a radio frequency signal. The high-linearity frequency mixer disclosed by the invention can be used for improving the linearity of the frequency mixer, improving the capacity of processing large signals and further improving the conversion gain of the frequency mixer.
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Description

technical field

[0001] The invention relates to a mixer, in particular to a mixer with high linearity in radio frequency identification. Background technique

[0002] In the radio frequency identification (RFID) communication system, the mixer is one of the most important circuit modules. It converts down to obtain an intermediate frequency or zero frequency signal, and converts up to obtain a radio frequency signal. Because the mixer has signals of two frequencies, and the RF signal has been amplified by the low-noise amplifier, the requirements for linearity and other indicators are relatively high. For the mixer circuit, there are generally two structures, one is an active mixer, namely the Gilbert structure, and the other is a passive mixer. Active mixers have better noise figure and gain, while passive mixers have higher linearity, so it is difficult to design active mixers with high linearity.

[0003] like figure 1 As shown, it is a circuit diagram of an existing G...

Examples

Embodiment Construction

[0019] like figure 2 Shown is the circuit diagram of the high linearity mixer in the radio frequency identification of the embodiment of the present invention. The embodiment of the invention includes a load circuit, a switch circuit and a transconductance circuit. The load circuit and the switch circuit and as figure 1 The circuit structure of the conventional Gilbert mixer shown is the same. The following only describes the transconductance circuit of the embodiment of the present invention. The transconductance circuit of the embodiment of the present invention includes a first NMOS transistor M 11 , the second NMOS tube M 12 , the first input DC blocking capacitor C 11 , the first bias resistor R 11 , The second input DC blocking capacitor C 12 , the second bias resistor R 12 .

[0020] The first NMOS transistor M 11 and the second NMOS transistor M 12 The source of the ground, the first NMOS transistor M11 and the second NMOS transistor M 12 The drains of the...