Multi-band Signal Transmission Research Articles

Design of 3-D Integrated SIW Multiband Bandpass Filter With Split-Type Extended Doublet Topology

A new class of 3-D integrated multiband bandpass filters (BPFs) based on substrate integrated waveguide (SIW) technology is presented in this work, for the first time. Split-type dual-extended doublet (SDED) coupling topologies are developed to propose these BPFs with a desired multiband response by the LEGO-style assembly of planar SIW resonant-mode blocks. These design schemes offer attractive and promising advantages with regard to compact size, low cost, flexible and expandable topology, as well as integration of high-density integrated circuits. For demonstration, dual- and triple-band BPFs are designed, fabricated, and measured. The measurement results are in good agreement with the simulation ones. Results indicate that the proposals can provide not only nice selective multiband signal transmission in such flexibly extensible topologies with new spatial schemes but also increase space utilization and reduce footprint.

A Bi-Directional Multi-Band, Multi-Beam mm-Wave Beamformer for 5G Fiber Wireless Access Networks

An autonomous beamformer demonstrates multi-beam and multi-band signal transmission and reception with wide field-of-view (FoV) self-steering beam-tracking/-forming for future extreme broadband and dynamic mm-Wave fronthaul applications operating in 5G new radio (NR) frequencies. The experimental results show the novel autonomous beamformer system covering full FoV beamforming (180°) with a wideband 22-40 GHz home-designed antenna array, demonstrating simultaneously multi-band (24.75 and 37 GHz) signals receiving with enhanced mobile multi-Gb/s transmission. A system testbed is further implemented to achieve a mm-Wave bi-directional link between remote radio unit (RRU) and user equipment (UE) in a fiber-wireless integrated network. A wide FoV autonomous signal sensing for angle-of-arrival (AoA) information in receiver is fed forward for mirror-reversed multi-Gb/s signal transmitting over a 10-km fiber and 0.56-m wireless link, addressing fast-changing complex 5G transceiver alignments. To the best of our knowledge, this is the first demonstration of an integrated autonomous beamformer for mm-Wave multi-beam and multi-band mobile applications in a fiber-wireless integrated radio access network.

A Novel Single Feedback Architecture With Time-Interleaved Sampling for Multi-Band DPD

With the increasing demand for multi-band signal transmission, power amplifier (PA) linearization has applied a variety of multi-band predistortion methods. However, as the number of carrier increases, the feedback path will be complex and high-sampling rate analog-to-digital converters (ADCs) will significantly increase the system cost. In this letter, to simplify the system structure and reduce the sampling rate for ADCs, a novel DPD method based on a single feedback architecture with time-interleaved sampling method is proposed. The time-interleaved sampling signals based on the low-sampling rate can be obtained by two ADCs, whose under-sampling factors are coprime. Then, the multi-band signals can be reconstructed due to its band sparsity to calculate the coefficients of the predistortion. If the frequency difference of the bands are bigger than the BW of the ADCs, the multi-band signals can be still reconstructed. Compared with previous approaches regarding the multi-band DPD, the proposed method can obtain good linearization performance and reduce the feedback sampling rate. Experimental results with the multi-band signals are presented to show the improvements.