Adaptive Millimetre-wave Integrated TranSmitters

毫米波能够实现超高的数据速率。然而，较高的传播损耗限制了覆盖范围。以大的直流功率为代价，通过使用具有大量活动路径的天线发射机，可以大幅增加覆盖范围和数据速率。在ADAMIS中，我们希望为毫米波系统探索新的架构和方法，通过在系统、电路和器件级别应用自适应来实现数据速率、传输距离和直流功耗之间的最佳平衡。为此，开发了一种自适应发射机前端，它具有多个可切换和可调的有源路径。在高达几厘米的极低覆盖范围(例如，用于车载通信)和/或低数据速率下，仅激活一条具有低方向性的有源天线路径。这些电路在低功率模式下运行，并且去激活矢量调制器。对于大距离(高达10米)和/或大数据速率(高达50 Gb/S)，所有有源天线路径包括。用于波束成形的矢量调制器被激活。在此模式下，电路以最大增益和输出功率运行。在毫米波频率，矢量调制器中所需的可变增益放大器强烈地改变其相位与需要复杂控制的增益。我们将研究解决这个问题的高级拓扑，例如通过级联带逆误差的级联。为了更好地理解和优化电路，我们推导了相关传递函数的解析表达式。对于参数(路径数、功率和矢量)的调整，我们研究和比较了两种方法：一是在毫米波频率扫描参数并测量接收强度或误码率；二是使用低功率2/5 GHz雷达对发射机和接收机进行定位。因此，可以可靠地提取最大距离的最佳传动角和距离。前端的开发采用了最新的IHP BiCMOS技术，工作频率为220-270 GHz。每条路径由天线、功率放大器、矢量调制器、混频器、频率倍增器和二进制相位调制器组成。将对几种天线结构和封装概念进行研究。为了测试所开发的发射机前端，将利用现有的实验室设备设计一台接收机。为了将功耗降到最低，并在本项目有限的资源内实现完全集成的发射机，我们将重点研究BPSK(二进制相移键控)调制，这种调制可以通过利用差动电路相位来实现，而直流功耗几乎可以忽略不计。因此，不需要耗电的数据转换器。由于高达50 GHz的大可用带宽，50 GB/S的高数据速率是可能的。在低数据速率和/或低距离模式下，可以实现超低DC功耗。

Millimetre-waves enable ultra-high data rates. However, the high propagation loss limits the coverage range. At the expense of a large dc power, the coverage range and the data rate can be massively increased by using antenna transmitters featuring a large number of active paths. In ADAMIS we want to explore novel architectures and methodologies for millimetre-wave systems allowing an optimum trade-off regarding data rate, transmission distance and dc power consumption by applying adaptivity at system, circuit and device level. For this purpose, an adaptive transmitter frontend is developed, which features multiple switchable and tuneable active paths. At very low coverage range up to a few centimetres (e.g. for on-board communication) and/or low data rates, only one active antenna path with low directivity is activated. The circuits operate in a low power mode and the vector modulators are deactivated. For large distances (up to 10 m) and/or large data rates (up to 50 Gb/s) all active antenna paths incl. vector modulators for beamforming are activated. In this mode, the circuits operate at maximum gain and output power. At millimetre-wave frequencies, the variable gain amplifiers required within the vector modulators strongly change their phase versus gain requiring a complex control. We will investigate advanced topologies solving this problem, e.g. by cascading stages with inverse errors. To better understand and optimise the circuits we derive analytical expressions for the relevant transfer functions. For the adjustment of the parameters (number of paths, power and vectors), we study and compare two approaches: First, by scanning the parameters at millimetre-wave frequencies and measuring the receive strength or bit error rate, and second, by employing a low-power 2/5 GHz radar for positioning of the transmitter and the receiver. Hence, the optimum transmission angles and distances can be reliably extracted up to large distances. The latest IHP BiCMOS technology is used for the development of the frontend operating at 220-270 GHz. Each path consists of an antenna, a power amplifier, a vector modulator, a mixer, a frequency quadrupler and a binary phase modulator. Several antenna structures and packaging concepts will be investigated. To test the developed transmitter frontend, a receiver using existing lab-equipment will be designed. To minimize the power consumption and to allow the realisation of a fully integrated transmitter within the limited resources of this project we will focus on BPSK (binary phase shift keying) modulation, which can be realised with almost negligible dc power consumption by exploiting the differential circuit phases. Hence, no power consuming data converters are required. Due to the large available bandwidth of up to 50 GHz, a high data rate of 50 Gb/s is possible. In the low data rate and/or low distance mode, ultra-low dc power consumption is possible.