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The article discusses factors influencing the bandwidth and performance of the Butler matrix, a passive beamforming network which feeds the phased array of antenna elements. Topics discussed include the active and passive beamforming networks, Butler matrix configuration, and potential applications of Butler matrix beamforming networks including channel simulator in massive multiple-input multiple-output (MIMO) systems and object detection and allocation.

Massive MIMO (mMIMO) phase and amplitude controlled networks are the key RF technology of 5G. However, available phase shifters and attenuators that provide phase and amplitude control are narrowband, with typical bandwidths of only 200 MHz and have control resolution no more than 7 bits for sub-6 GHz and 6 bits for the mmWave bands. So building test systems to cover the 5G bands requires a significant investment in narrowband equipment, with performance insufficient to meet high test accuracy requirements. This article describes wideband designs for controlling phase and amplitude, offering the widest bandwidth--1.7 to 6 and 24 to 40 GHz--and highest resolution and accuracy commercially available. Two modules cover the 5G microwave and mmWave frequency bands with full 360 degree control and dynamic range to 50 dB and a resolution and accuracy of 0.1 dB and 1 degree sub 6 GHz and 0.2 dB and 2 degrees at mmWave. These phase and amplitude control modules serve as building blocks for beamforming, mMIMO, over-the-air (OTA) and multichannel signal simulator test systems. With their wideband coverage, resolution and accuracy, building test scenarios is simple and fast, reducing cost. [ABSTRACT FROM AUTHOR]

The article discusses optimization of effective cable assemblies for every application requirement. Among the topics include the requirements needed of cable assemblies for phased array systems, problems in phased array systems that should be addressed by cable assembly manufacturers, and performance requirements expected by customers for test cable assemblies. It says that cable assemblies are used as connections between components within antenna feeds, test platforms, and racks.

A substrate integrated waveguide (SIW) bandpass filter is proposed in this article, which uses proximity coupling structures and slot loaded quarter SIW resonators to implement a cascaded triplet (CT) filter Electrical coupling is realized with the novel proximity coupling structure, while the size of a quarter SIW resonator (QSIWR) is reduced by 43 percent, when loaded with a slot. By introducing magnetic cross coupling into the electric main coupling path, a C-Band CT filter is designed, which has a transmission zero at the upper stopband The measured results show good performance and agree well with the simulated results. [ABSTRACT FROM AUTHOR]

The article focuses on the use of quarter substrate integrated waveguide resonator (QSIWR) and a fractal shaped defected structure (FDS) in designing substrate integrated waveguide (SIW) bandpass filters. It states that QSIWR and FDS are used because of various benefits including simple structure, extra transmission zero and compact size. It further presents various figures explaining the working of QSIWR.