Beamformer With Constant-Gm Vector Modulators and Its Spatial Intermodulation Distortion
Beamformer With Constant-Gm Vector Modulators and Its Spatial Intermodulation Distortion
复制标题
恒定Gm矢量调制器的波束形成器及其空间互调失真
DOI：
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发表时间：
2017
影响因子：
5.4
通讯作者：
F. V. van Vliet
中科院分区：
文献类型：
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作者：
Michiel C. M. Soer;E. Klumperink;D. van den Broek;B. Nauta;F. V. van Vliet
模拟自适应波束成形接收机中的空间干扰抑制可改善波束成形网络之后电路的失真性能，但易受波束成形网络自身非线性的影响。本文对模拟有源相控阵接收机中的互调产物抵消进行了分析，并验证了在1.0 - 2.5 GHz频段用于低功率应用的四单元自适应波束成形接收机中的失真改善情况。在此架构中，提出了一种恒定跨导（Gm）矢量调制器，它能产生精确的等距方形星座图，从而为每个天线单元设计出可复制的切片式前端。通过将跨导移至射频端，功率降低了四倍，同时实现了输入阻抗匹配。采用65纳米工艺实现时，每个天线单元功耗在6.5到9毫瓦之间，并且由于互调失真降低，在频带内和波束外的三阶交截点达到 +1到 +20 dBm。
Spatial interference rejection in analog adaptive beamforming receivers can improve the distortion performance of the circuits following the beamforming network, but is susceptible to the nonlinearity of the beamforming network itself. This paper presents an analysis of intermodulation product cancellation in analog active phased array receivers and verifies the distortion improvement in a four-element adaptive beamforming receiver for low-power applications in the 1.0–2.5-GHz frequency band. In this architecture, a constant-Gm vector modulator is proposed that produces an accurate equidistance square constellation, leading to a sliced frontend design that is duplicated for each antenna element. By moving the transconductances to RF, a fourfold reduction in power is achieved, while simultaneously providing input impedance matching. The 65-nm implementation consumes between 6.5 and 9 mW per antenna element and shows a +1 to +20 dBm in-band and out-of-beam third-order intercept point due to intermodulation distortion reduction.