NMOS transistor based 90-degree phase shifter

Abstract

The invention relates to a NMOS transistors based 90-degree phase shifter, which belongs to the technical field of the design of radio frequency microwave integrated circuits. The 90-degree phase shifter consists of an input end, a first second-order all-pass filter and a second second-order all-pass filter which are driven in parallel, a first output end and a second output end, wherein the first second-order all-pass filter comprises two NMOS transistors which are connected in series, a capacitor and two capacitors and resistors which are connected in parallel; and the second second-order all-pass filter comprises two NMOS transistors which are connected in series, a capacitor and two capacitors and resistors which are connected in parallel. The NMOS transistor based 90-degree phase shifter achieves 90-degree phase-shifting in a small area by using a CMOS process with low cost and low power consumption, and has the following two advantages that: firstly, the 90-degree phase shifter has no transmission loss and can adjust the gain thereof through an active element; and secondly, the 90-degree phase shifter is compatible with a standard CMOS process, and has low cost, low power consumption, high integration and wide working band.

Description

technical field [0001] The invention relates to a 90° phase shifter, in particular to a 90° phase shifter based on NMOS transistors, and belongs to the technical field of radio frequency microwave integrated circuit design. Background technique [0002] The 90° phase shifter is a circuit used to generate quadrature signals I and Q. It is one of the basic modules in radio frequency microwave integrated circuits, and is often used in the generation of quadrature local oscillation signals in modulation and demodulation modules. The performance of a 90° phase shifter is determined by the accuracy of the phase difference and amplitude difference between its output signals. figure 1 It is a schematic diagram of the basic structure of a 90° phase shifter in the prior art. Such as figure 1 As shown, the prior art 90° phase shifter generally consists of two passive second-order all-pass filters driven in parallel, and each passive second-order all-pass filter is composed of a gain ...

AI Technical Summary

Problems solved by technology

[0003] The present invention provides a 90° phase shifter based on NMOS transistors in view of the shortcomings of the prior art 90° phase shifter with large transmission loss, high manufacturing cost and difficulty in integration

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