Design of multiplexer with improved manifold line and hairpin filter

In this paper, a five-channel multiplexer is proposed for L-band applications, which is mainly composed of traditional hairpin filters and improved manifold-line structures. Through optimizing the manifold lines, good impedance matching is achieved. The simulated and measured results demonstrate that the multiplexer can realize five channels in the frequency band of $1.0 \sim 2.0 \mathrm{GHz}$, and each channel has the bandwidth of 200MHz and the low return loss less than -20.0 dB.