In the first part of this thesis a basic theory of retrodirective antenna arrays and their particular parts – antennas and mixers is summarized. Further, there is a basic summary of possibilities for an usage of retrodirective antenna arrays for an information transmission. The second part deals with the concrete retrodirective antenna array design. The design starts with creation of an antenna array model for MATLAB software. Then a suitable structure for further design is chosen. Further, particular parts of retrodirctive antenna array – a patch antenna, a mixer, a low-pass filter, a bandstop filter, a signal combiner and a Wilkinson power divider are designed and analyzed in Ansoft Designer software. For the patch antenna analysis also CST Microwave Studio software is used. The following part deals with the realization of particular parts of the retrodirecive antenna array and its parameters measuring.

As communication technology evolves, the focus shifts to 5G. The discussion of 5G cannot be separated from a discussion of related antenna systems. Chapter 1 is a brief introduction to our work, which is an antenna array for a 5G communication system operating in the band 3.4 to 3.8 GHz. This is a common band for 5G in Europe. Background and theory are presented in Chapters 2 and 3. In Chapter 4, the design has been simulated with the software CST Studio Suite. We study an antenna group that consists of four linear arrays that together cover all directions. The gain eventually reaches 12dB in each of the main directions after optimization. Based on simulation, this gain could be implemented as described in Chapter 5. The specification requires that the antenna should have four main directions with high directivity and a reasonable performance elsewhere. The realized gain is 11 dB for the four main directions. Our data shows that the arrays have two different work modes depending on feeding: one as a directive antenna with 11 dB gain, the other as an omnidirectional antenna with 7.5 dB gain. High directivity is very important for 5G communication. A summary with conclusions is given in Chapter 6 where also some improvements are suggested.

In recent years, multiple-input multiple-output (MIMO)systems appear to be very promising since they can provide highdata rates in environments with sucient scattering byexploiting the spatial domain. To design a real MIMO wirelesssystem and predict its performance under certain circumstances,it is necessary to have accurate MIMO wireless channel modelsfor dierent scenarios. This thesis presents dierent models forindoor MIMO radio propagation channels based on 5.2 GHz indoorMIMO channel measurements.The recent research on MIMO radio channel modeling isbriey reviewed in this thesis. The models are categorized intonon-physical and physical models. The non-physical modelsprimarily rely on the statistical characteristics of MIMOchannels obtained from the measured data while the physicalmodels describe the MIMO channel (or its distribution) via somephysical parameters. The relationships between dierent modelsare also discussed.For the narrowband case, a non line-of-sight (NLOS)indoor MIMO channel model is presented. The model is based on aKronecker structure of the channel covariance matrix and thefact that the channel is complex Gaussian. It is extended tothe line-of-sight (LOS) scenario by estimating and modeling thedominant component separately.As for the wideband case, two NLOS MIMO channel modelsare proposed. The rst model uses the power delay prole and theKronecker structure of the second order moments of each channeltap to model the wideband MIMO channel while the second modelcombines a simple single-input single-output (SISO) model withthe same Kronecker structure of the second order moments.Monte-Carlo simulations are used to generate indoor MIMOchannel realizations according to the above models. The resultsare compared with the measured data and good agreement has beenobserved. / <p>NR 20140805</p>

The extensive industrialization and human expansion has caused environmental protection wildlife conservation to become paramount concerns of the 21st century. The ecosystems of oceans and seas have particularly been affected due to activities like oil spills and increased fishing. This has led to a growing interest in monitoring of the oceans and marine animals to detect signs of distress in aquatic species. However, acquisition of data from oceans to land has been a challenging and expensive task. The concept of Internet of Sea provides a solution to this data transfer between the ocean nodes, like animal tags or deployed floating transceivers, and our land Internet, and can potentially eliminate the need of expensive monitoring ships or underwater cables. The Internet of Sea is system that comprises of sensor nodes in the form of detachable marine animal tags as the data acquisition platforms and distributed floating transceivers as the intermedium nodes which then transfer the data to the base-stations located on lands. The data acquired by animal tags are first to be stored in the tag, and once the tag comes to the sea surface, the data is transferred to the nearby floating transceivers. The floating transceivers have multi- hopping capability so the data can be passed to the land base-stations through a small number of transceivers. Due to the specific geometric shapes and size constraints of the tag and floating transceivers, as well as the harsh ocean environment, novel integrated antennas are required for this type of system. In this thesis, we propose several antenna designs suitable for Internet of Sea applications. The first design is a quasi-isotropic Antenna in Package (AiP), operating in the Bluetooth band, which has been designed for semi-real-time monitoring. Secondly, a large frequency-ratio dual- band microstrip antenna array, working at Extended Global System for Mobile communications (E-GSM900), Long Range (LoRa), and Bluetooth bands, has been designed for large-area wireless communication. Lastly, a circularly polarized microstrip antenna array has also been designed for Global Positioning System (GPS). Throughout the work, the measured results are consistent with the design strategies and simulation results.

In this work, an innovative approach for effective modeling of substrate integrated waveguide (SIW) devices is firstly proposed. Next, a novel substrate integrated waveguide power splitter is proposed to feed antenna array elements in series. This feed network inherently provides uniform output power to eight quadrupole antennas. More importantly, it led to a compact configuration since the feed network can be integrated inside the elements without increasing the overall array size. Its design procedure is also presented. Then, a series feed network was used to feed a novel compact omnidirectional antenna array. Targeting the 5G 26 GHz mm-wave frequency band, simulated results showed that the proposed array exhibits a broad impedance bandwidth of 4.15 GHz and a high gain of 13.6 dBi, which agree well with measured results. Its attractive features indicate that the proposed antenna array is well suitable for millimeter-wave wireless communication systems.

No description available.

This dissertation research presents a comprehensive study to answer the question of “Can it be possible to integrate a high gain optically transparent antenna array directly on top of solar cells?”. The answer to such question is extremely important in space exploration where very small satellites have been extensively employed. Due to their small mass and size, those small satellites create challenges for one to mount the antennas, and the challenge is further increased when a high gain antenna is need for more communication capacity. Based on feasibility studies, the dissertation concludes that it is possible to do such an integration, and then proceeds to present the approaches for design and integration. On the element level, the thesis presents research in assessing the effects between a planar antenna integrated on the solar cell and the photovoltaic cell. A series of experiments were designed to perform assessments for antennas operating from C to X bands. It is concluded that a commercial triple junction space–certified solar cell normally would decrease the gain of the antenna to 2–3 dB and is not affected by the working states of solar cells. The shadow of the antenna casts on solar cells, however, is not significant (less than 2%). The thesis also provides a model of a common space solar cell that helps to explain the gain loss. The model was validated by experimental data, and it was utilized to predict iv a possible custom design of solar cell where with a minimal design modification, it would facilitate less gain loss of the antenna integrated on top. On the array level, the research surveys different high gain antenna array design and then focus on an optimal sub–wavelength reflectarray design. The final antenna array design is a 30 cm by 20 cm, X band (8.475 GHz) reflectarray that shows 94% transparency, 24 dB gain, and higher than 40% aperture efficiency. The design is then prototyped and tested on actual solar panel. The measurement of the reflectarray placed on the solar panel showed a gain of 22.46 dB and an aperture efficiency of 29.3%. While those results are considered excellent, the thesis continues to address the reasons for reduction of the antenna’s performance due to the solar panel, through both theoretical analysis and experiments.

In this thesis, the design fabrication and characterization of a 2 x 8 microstrip planar antenna array operating at the 60 GHz band for Wireless Gigabit Alliance (WiGig) applications are presented. The trade-offs among low production costs, performance, and ease of fabrication were considered. Full-wave electromagnetic (EM) analysis is implemented for the antenna design by using |ANSYS®High Frequency Structural Simulator (HFSS), a finite-element EM solver. The antenna structure consists of two layers, where each array element is a Conductor-Backed Coplanar Waveguide (CB-CPW) loop-fed patch antenna. The bottom layer houses the transmission line and feeding circuitry, while the patch antennas are built on the top layer. The transmission line is designed on microfabrication-compatible quartz substrate, and the patches on a Rogers RO3003 Printed Circuit board (PCB) substrate. The CPW network's right-angle bends are optimized with chamfered lines. Air bridges are used to suppress the parasitic coupled slot line mode of the CPW line divisions. Results of the EM analysis show that the array covers the United States (US) 60 GHz unlicensed band (57-64 GHz), and has a maximum realized gain of 18 dB at 61 GHz on the broadside direction. The antenna design is later fabricated combining microfabrication and standard PCB procedures.

No description available.

The use of phased array antennas in present day technology is limited, primarily due to the extremely high cost of implementation. This cost is contributed to the expense of phase shifters, which are the traditional method of beam steering in phased arrays. The need to alleviate this cost and avail the technology for commercial use necessitates study into alternative mechanisms for accomplishing beam steering. To this effect, this research is an exploration of one such mechanism. To characterize mutual coupling between microstrip patch antennas and explore its practicality as a feed mechanism, it is necessary to understand the factors controlling the phenomenon. A parametric study of the spacing between patch antennas and the consequent coupling is presented, the results of which are discussed in detail. further study into bandwidth extension and steer controlling techniques are also shown, with discussion on the practicality and future of the mechanism as a candidate for widespread application.