RIA: A New Approach to Microwave/Millimeter-Wave Transmitters

需要紧凑的高功率源， 微波和毫米波雷达的应用- 波程 固态功率放大器的输出功率水平 在该频率范围内的设备是有限的。 一 本研究探讨的可能解决方案 启动补助金是连贯地将联合收割机的产出 数以百计的活动设备，加载一个2- 三维金属网格的周期等于 自由空间波长的一部分。 此active 表面既是源又是天线。 的设备 可以被布置在栅极反馈中 配置. 这种类型的振荡器具有广泛的 频率调谐范围，如大多数 应用. 振荡的活性表面被背衬 具有电可变的调谐镜， 反射系数 这面镜子是另一种金属 栅极加载有变容二极管。 的电容 二极管，因此， 该调谐表面是偏置相关的。 镜子 向振荡器表面提供正反馈， 这对于设备锁定到单个 模式 例如，在雷达中，信号通常是 以脉冲形式传输。 如果发射机 本身不能以高速率打开和关闭， 可以使用开关有源表面。 该表面 由一个装有pin二极管的栅极组成， 电开关从传输的波 振荡器栅极 该系统结构紧凑，重量轻 重量，因为它是由一堆平面 装载了不需要 大功率电源。 它是多功能的，例如， 肖特基二极管的另一个有源表面放置在 与振荡器并联的电路可能有一个变量 用于波束控制或波束形成的相移 应用程序，或者可以用作乘数。 在 此外，该平面结构适合于晶片， 规模或模块化集成。

There is a need for compact, high-power sources for radar applications in the microwave and millimeter- wave range. The output power levels of solid-state devices in this frequency range are limited. A possible solution to be explored in this Research Initiation Grant is to coherently combine the outputs of hundreds of active devices that load a two- dimensional metal grid with a period equal to a fraction of a free-space wavelength. This active surface is an antenna as well as source. The devices can be MESFETs arranged in a gate-feedback configuration. This type of oscillator has a wide frequency tuning range, as is required in most applications. The oscillating active surface is backed with a tuning mirror that has an electrically variable reflection coefficient. This mirror is another metal grid loaded with varactor diodes. The capacitance of the diodes, and therefore the reflection coefficient of this tuning surface, is bias dependant. The mirror provides positive feedback to the oscillator surface, which is necessary for the devices to lock to a single mode. In a radar, for example, the signal is usually transmitted in pulses. In cases when the transmitter itself cannot be switched on and off at a high rate, a switching active surface can be used. This surface consists of a grid loaded with pin diodes, and it electrically switches the wave transmitted from the oscillator grid. This system is compact and light weight, since it consists of a stack of planar dielectrics loaded with solid-state devices that do not require large power supplies. It is versatile, for example, another active surface of Schottky diodes placed in parallel with the oscillator could have a variable phase shift for beam steering or beam forming applications, or can be used as a multiplier. In addition, the planar structure is suitable for wafer- scale or modular integration.