RF/microwave bandpass filters (BPFs) are fundamental components in high-frequency RF transceivers. On the transmitter side, they limit the transmitted RF signal bandwidth by suppressing out-of-band spurious signals and intermodulation products, which are primarily generated by the nonlinear active stages and can affect other RF systems. On the other hand, in the receiver, they reject out-of-band interfering/jamming signals and noise. Whereas a large variety of microwave BPFs have been proposed in the technical literature for multiple technologies (e.g., [1] and [2]), most of these BPF devices achieve their filtering functionality by means of the frequency-selective power reflection processing of the RF input signal. This means that those RF signals allocated within the operational bandwidth of the BPF are transmitted to the output terminal (with some tolerable added in-band loss and reflective-type filter, hence decreasing the mixer conversion gain.

中文翻译：

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避免射频隔离器：用于高级射频前端的无反射微波带通滤波组件

射频/微波带通滤波器 (BPF) 是高频射频收发器中的基本组件。在发射机方面，它们通过抑制带外杂散信号和互调产物来限制发射的射频信号带宽，这些信号和互调产物主要由非线性有源级产生并可能影响其他射频系统。另一方面，在接收器中，它们拒绝带外干扰/干扰信号和噪声。虽然技术文献中已经针对多种技术（例如 [1] 和 [2]）提出了种类繁多的微波 BPF，但这些 BPF 设备中的大多数通过频率选择性功率反射处理来实现其滤波功能。射频输入信号。