Design and Implementation of an Ultra-wide Band Variable Gain Amplifier Based on Dual Gain Control Technology

To achieve an ultra-wide band variable gain amplifier (UWB-VGA) with the wide gain variable range and a good gain flatness for each varied gain possible in the UWB frequency band, a dual gain control (DGC) technology, which is composed of an amended current mirror gain control structure and a dynamic signal feedback gain control structure, was proposed. Based on the proposed DGC technology, an ultra-wide band variable gain amplifier for 3.0-6.0 GHz band was designed. Both the schematic and the layout of the UWB-VGA were completed. Considering the parasitic and coupling effects of the layout, device structure and process, package generation in the RF band, the electromagnetic co-simulation of schematic and layout was implemented by momentum simulation tools. Results show that by adjusting the two control voltages of the dual gain control unit, the wide variable range of gain and good gain flatness in the frequency of 3.0-6.0 GHz are obtained. The gain variation range gets 5.5 dB and the gain flatness is less than or equal to ±2.5 dB for every variable gain when the dynamic signal feedback gain control voltage V_{ctrl_2} is 5.00 V and the amended current mirror gain control voltage V_{ctrl_1} changes from 2.50 V to 3.20 V. S₁₁ and S₂₂ are less than -10.0 dB, and the input and output match well in the frequency of 3.0-6.0 GHz.