毫米波单片低噪声放大器的研制

Design and implementation of monolithic millimeter wave low noise amplifiers

采用OMMIC0.18μm GaAs pHEMT工艺,研制了两级和三级2种毫米波单片低噪声放大器.以最小噪声度量为设计依据,通过适当提高偏置电流的方法改善毫米波频段的增益,使得放大器在保持噪声系数较小的同时获得较高的增益.两级低噪声放大器采用串联负反馈结合并联负反馈的结构,可以获得比较平坦的增益;三级低噪声放大器采用三级相似的串联负反馈结构级联,可以紧凑结构、在相同的芯片尺寸下获得较高的增益,2种低噪声放大器芯片的尺寸均为1.5mm×1.0mm.测试结果表明,在28-40GHz频段内,两级低噪声放大器增益最大为15.4dB、噪声系数最小为3.2dB;三级低噪声放大器增益最大为24.8dB、噪声系数最小为2.73dB,达到预期目标.

Two millimeter wave low noise amplifiers（LNA） are designed and implemented with an OMMIC 0.18μm GaAs pHEMT（pseudomorphic high electron mobility transistor） process.The amplifiers are designed based on minimum noise measure,and a method of increasing bias current is adopted to improve the gain.Thus the LNA can obtain higher gain while keeping a low noise figure at a millimeter wave frequency band.The two-stage LNA uses series and parallel feedback in different stages to achieve flat gain.The three-stage LNA uses three series feedback stages to achieve high gain in the same chip size.The chip sizes of both the LNAs are 1.5mm×1.0mm.In the frequency range of 28 to 40 GHz,the two-stage LNA achieves a maximum gain of 15.4dB and a minimum noise figure of 3.2dB,and the threestage LNA achieves a maximum gain of 24.8dB and a minimum noise figure of 2.73dB.According to the test results,the amplifiers can operate well at 28 to 40 GHz.