Simulated reflection type I-Q vector modulation circuit based on GaAs (Generally accepted Auditing standards) HBT (Heterojunction Bipolar Transistor) device

Abstract

The invention discloses a simulated reflection type I-Q vector modulation circuit based on a GaAs (Generally accepted Auditing standards) HBT (Heterojunction Bipolar Transistor) device, mainly solving the problems of large chip-occupied area ratio and high cost of the traditional modulation circuit and comprising a 3-dB Lange coupler (1), two simulated reflection type attenuators (6, 7) and a 3-dB Wilkinson power combiner (10), wherein the straight-through port of the 3-dB Lange coupler is outputted to one input end of the power combiner (10) after directly subjected to phase shift by the first attenuator (6), and the coupling port of the 3-dB Lange coupler is outputted to the other input end of the power combiner (10) after directly subjected to phase shift by the second attenuator (7), wherein the collector electrodes of a gallium arsenide hetero-junction bipolar transistor of each simulated reflection type attenuator are respectively connected with resistors R3 and R4 in parallel for reducing a reflection factor gamma when Vb is equal to 0, and the transmission electrodes of the gallium arsenide hetero-junction bipolar transistors are respectively connected with inductors L1 and L2 in series for offsetting a parasitic effect generated by the HNT device. The invention can be used for generating I-Q modulation signals or carrying out frequency conversion.

Description

technical field [0001] The invention belongs to the technical field of integrated circuits, in particular to a reflection type I-Q vector modulation circuit, which is used in digital communication to generate I-Q modulation signals or perform frequency conversion. Background technique [0002] Traditionally, there are two main implementation structures for vector modulators in microwave and millimeter wave applications. The first is composed of two quadrature bi-phase modulators through a 3-dB power combiner; the second is composed of a variable attenuator and a 360° variable phase shifter. Although in the second structure, the insertion loss is very small, it requires the attenuator to have a fixed phase and the phase shifter to have a fixed insertion loss, which makes the circuit design very difficult. Therefore, in microwave and millimeter wave applications, the first structure consisting of two-phase variable analog reflective attenuators is often widely used. [0003]...

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Problems solved by technology

This structure can achieve a better symmetrical constellation diagram, but it occupies a relatively large chip area and costs relatively high

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