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Design of WiMAX Transmission Networks
Published in Amitabh Kumar, Mobile Broadcasting with WiMAX: Principles, Technology, and Applications, 2014
The closed loop MIMO systems (advanced antenna systems and beam forming) is an optional feature in the Mobile WiMAX IEEE 802.16e standards. The beam forming techniques use an antenna array at the transmitter and receiver along with advanced signal processing. The amplitude and phase of the signals supplied to the antennas are so phased as to change the direction of the beam toward the location of the receiver (software for beam forming antennas is supplied by vendors such as Arraycom®). The higher antenna gains achieved with beam forming together with reduction of interference at the receiver lead to significantly improved link performance. The beamforming needs to be operative within the selected frame intervals (e.g., 5 ms to 20 ms). The advanced processing capabilities available today in the chipsets make the implementation of closed loop MIMO systems and advanced antenna techniques, including beam forming, practical.
Multidimensional High-Resolution Parameter Estimation with Applications to Channel Sounding
Published in Yingbo Hua, Alex B. Gershman, Qi Cheng, High-Resolution and Robust Signal Processing, 2017
Martin Haardt Reine, S. Thomä, Andreas Richter
The propagation path directions in Figure 5.6 as seen from the mobile and the base station sides are resolved with the help of antenna arrays deployed on both ends of the link. By applying the sequential data recording principle described in Subsection 5.4.3, an observed data vector can be constructed that contributes up to four spatial dimensions, i.e, two on the Tx and two on the Rx side, to the harmonic data model as described in (5.2.1). With properly designed antenna arrays, we can resolve azimuth and elevation angles on both sides of the link. The antenna array architecture is defined by the spatial arrangement (“array geometry”) of the antenna elements and by the response functions of the antenna elements.
Importance and Uses of Microstrip Antenna in IoT
Published in Praveen Kumar Malik, Planar Antennas, 2021
Antenna array of microstrip patch is used to achieve higher gain (directivity) and to give diversity. These two parameters are used in MIMO and it also increases communication reliability. The selection of feeding method is really important as it affects bandwidth, size of patch, return loss, and smith chart. There are four most popular feeding methods present: coaxial probe, microstrip line, aperture coupling, and proximity coupling. Among all these, microstrip line feed is chosen as it is easy to fabricate, easy for impedance matching, and has ease in modelling [8].
Beamforming networks using the Nolen matrix for 5G applications
Published in Waves in Random and Complex Media, 2023
Hussam Keriee, Mohamad Kamal A. Rahim, Osman Ayop, Nawres Abbas Nayyef
Recently, phased antenna arrays and beamforming have gained great significance in several fields such as wireless communication systems specifically for fifth-generation (5G) technology. Generally, an antenna array is controlled by a feeding network, which maintains the amplitude and phase shift of each antenna element [1]. In such a system, the radiation beam is formed by the antenna array toward the desired direction. With this advantage, typically there are three main types of feeding networks controlling the antenna array; Parallel-feed network, series-feed network, and matrix-based network [2]. In parallel and series feed networks, the antenna array requires a large tuning wide phase shifters that are not able to generate multi beams. In contrast, a matrix-based feeding network consists of components such as a hybrid coupler, crossovers, and phase shifters [3]. In addition, a matrix-based feeding network has the feature of generating multi-beams concurrently. Several matrix feeding networks have been introduced such as the well-known Butler matrix, Blass matrix, and Nolen Matrix [4–6].
Low-Profile Wide-Scan Closely Spaced Antenna Array of Electrically Small Antennas
Published in IETE Technical Review, 2018
Harish Naik, Abhishek K. Awasthi, A. R. Harish
Antenna array is one of the important components of modern radar and communication systems [1]. With the new development in these fields, the requirements of compact wideband and wide-scan antenna array are also increasing. The performance of a phased array antenna with the number of elements for aperture distribution was discussed by Singh et al.in [2]. A planar non-resonant array with ultra-low side lobe level for airborne radar applications was designed by Christopher et al. [3]. A broadband multilayer patch antenna array for Ku-band application was proposed by Ding et al. [4]. In [5], the authors presented a substrate integrated waveguide (SIW)-slot antenna for wide angle scanning phased array. A wide beam microstrip patch antenna with metal wall for wide angle scanning phased array was proposed by Yang et al. [6]. A wide scan phased array antenna based on metamaterial electrical LC slot and L-probe fed cavity backed patch antenna for X-band applications was proposed by Dadashazdeh [7]. The above-mentioned antenna arrays provide very wide angle scanning but the size of the unit cell is also large. To design the compact antenna array, either the size of the antenna element or the distance between the elements is needed to reduce. An electrically small antenna (ESA) [8] can be chosen as a basic element for the antenna array. Since the size of the antenna element is small, the elements can be placed very close to each other which results in large mutual coupling between them. The mutual coupling which is an inherent property of the antenna array can be utilized in an efficient way to design the antenna array for the enhanced performance [9]. Several tightly coupled arrays are proposed, in the literature, which utilize the inter-element coupling to enhance the performance of the antenna array. A broadband antenna array design based on current sheet concept is proposed by Munk [10,11]. A planar ultra-wideband modular array of tightly coupled dipole array was proposed by Holland [12].
One- and two-dimensional antenna arrays for microwave wireless power transfer (MWPT) systems and dual-antenna transceivers
Published in International Journal of Electronics, 2018
Yo-Sheng Lin, Chun-Hao Hu, Chi-Ho Chang, Ping-Chang Tsao
In an antenna array, the mutual coupling effect results in the element radiation patterns being dissimilar. Therefore, the pattern multiplication principle is not applicable for obtaining the array radiation pattern. The mutual coupling effect is normally characterised by the mutual impedance Zij (with antenna element j excited), which can be expressed as