This letter presents a novel concept of beam-steerable transponder based on antenna array and phased modulators. The steerability of the beam is achieved by optimally delaying the modulated reflected signal at each antenna element (i.e., changing the phase in frequency domain) with load modulation technique. In this manner, the reflected backscattered signal power can be maximized at one particular direction. The approach makes transponder to collect ambient waves from any direction and further modulate and redirect it to any other direction. The results obtained through experimentation proves the feasibility of omnidirectional transponder and pave way for future lower power smart devices. The transponder functions in the Wi-Fi frequency band of 2.4 GHz.

中文翻译：

---

基于天线阵列和相控调制器的波束可控应答器


这封信提出了一种基于天线阵列和相控调制器的波束可控应答器的新颖概念。波束的可操纵性是通过使用负载调制技术对每个天线元件处的调制反射信号进行最佳延迟（即改变频域中的相位）来实现的。以这种方式，反射的反向散射信号功率可以在一个特定方向上最大化。该方法使应答器能够收集来自任何方向的环境波，并进一步调制并将其重定向到任何其他方向。通过实验获得的结果证明了全向转发器的可行性，为未来低功耗智能设备铺平了道路。应答器在 2.4 GHz Wi-Fi 频段工作。