Bendable wireless sensors and millimetre-wave transmitters using thinned SiGe BiCMOSAcronym: Bend-IT

Bend-IT旨在探索和展示世界上第一个在毫米波频率下工作的机械灵活的无线传感器。该项目基于非常快速的硅双极互补金属氧化物半导体（BiCMOS）技术，其厚度小于20 µm，以实现可弯曲性。该技术具有传输频率高达500 GHz的晶体管。因此，200 GHz的非常高的工作频率是可能的，从而大大减小了天线尺寸并允许其集成在芯片上。这降低了未来物联网（IoT）领域应用的电路尺寸和成本。将使用基于BiCMOS的温度、光和/或压力传感器。电源由我们的合作伙伴Varta提供的柔性薄膜电池实现。因此，极薄且可弯曲的有源毫米波传感器系统首次成为现实。关键的科学问题和相应的挑战如下：在如此高的频率下，减薄如何影响器件（如天线、晶体管、传输线、电容器、电感器和电阻器）和电路？作为一个有前途的副作用，减薄将降低衬底损耗，提高器件的性能。在如此高的频率下，哪些冲击具有弯曲和诱导的机械应力？如果紧凑的芯片被弯曲，我们如何在毫米波频率下测量它们？我们如何对变薄和弯曲进行建模？可以通过调整现有器件模型的参数来考虑减薄。然而，弯曲建模所需的表征在毫米波频率下具有挑战性。在这里，我们利用在弯曲条件下通过集成天线进行非接触式系统测试是可能的。将研究几种方法来减轻和补偿弯曲对系统的影响。示例如下：具有对弯曲、负反馈和电路拓扑的低灵敏度的电流反射镜，该电路拓扑表现出作为机械应力的函数的相反趋势。为了实现具有给定资源的完整前端，模拟调制是目标。传感器调制200 GHz振荡器。借助于200 GHz功率放大器，调制的传感器信号被放大以产生超过20 mW的输出功率。最后，信号通过片上天线辐射。

Bend-IT aims at exploring and demonstrating the world-wide´s first mechanically-flexible wireless sensors operating at millimetre-wave frequencies. The project is based on a very fast silicon bipolar complementary metal-oxide-semiconductor (BiCMOS) technology, which is thinned below 20 µm to enable bendability. The technology features transistors with transit frequencies up to 500 GHz. Hence, very high operation frequencies of 200 GHz are possible, thereby massively reducing the antenna size and allowing its integration on the chip. This decreases circuit dimensions and costs for applications in the area of the future internet of things (IoT). BiCMOS based temperature, light and/or pressure sensors will be used. Power supply is enabled by flexible thin-film batteries provided by our partner Varta. Hence, for the first time, extremely thin and bendable active millimetre-wave sensor systems are realizable.The key scientific questions and corresponding challenges are as follows: How does the thinning impact devices (such as the antenna, transistors, transmission lines, capacitors, inductors and resistors) and circuits at such very high frequencies? As a promising side effect, the thinning will lower the substrate losses and improve the performances of the devices. Which impacts have the bending and the induced mechanical stress at such high frequencies? How can we measure the compact chips at millimetre-wave frequencies if they are bended? How can we model the thinning and bending? The thinning can be considered by adapting the parameters of existing device models. However, the characterization required for the modelling of the bending is challenging at millimetre-wave frequencies. Here we take advantage that in bended condition a contactless system testing via the integrated antennas is possible. Several approaches will be investigated to mitigate and compensate the system impact of bending. Examples: current mirrors with low sensitivity against bending, negative feedback and circuit topologies exhibiting opposite trends as function of mechanical stress. To realise a complete frontend with the given resources, analogue modulation is targeted. The sensor modulates a 200 GHz oscillator. By means of a 200 GHz power amplifier the modulated sensor signal is amplified to produce an output power beyond 20 mW. Finally, the signal is radiated via the on-chip antenna.