الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 165 |  |  |
| | | from | 165 | | |
Abstract
The total number of mobile subscriptions has constantly been increasing in the last few decades. Of course, there are continuous updating requirements in each mobile generation, and these recent requirements and challenges foster antenna researchers in different communities to develop new flexible antenna systems that can meet the needs of the mobile communication future. The most critical problem facing the next generation of wireless communication is utilizing the system integration over their counterparts in present networks that suffer from higher complexity, costs and losses. According to that, the next generation of wireless communication systems consider the active integrated antenna array technologies as an essential part of those systems. Therefore, the coexistence of active integrated antenna technologies becomes the inevitable trend of future next-generation wireless communication systems.
In this thesis, the transition from 3G/4G to 5G mobile networks, have been studied. The thesis focused on the system components such as power amplifiers and active integrated antenna that can be utilized in mobile communication applications. Different designs have been explained, fabricated, and measured for better validation of the design theory and analysis for proposed antennas, power amplifiers, filters, diplexers, MIMO antennas, and arrays.
This thesis is started by designing a wideband antenna array, which is 4*1 elements from a double-sided printed dipole antenna. The proposed antenna array uses microstrip technology with λg/2 spacing between the elements @ 3.8 GHz. However, the proposed spacing makes the distance between the elements less than λg/2 at the lower frequency of the operating bandwidth.
In the second step, a 6-W GaN HEMT PA transistor device CGHV1F006S is used to design a wideband PA. The proposed PA is biased as deep Class AB due to its linearity and efficiency which have been well-adjusted. The PA is designed to operate at frequencies between 3.6 and 4 GHz. In order to maximize the presented PA performance across the operating bandwidth, load-pull analysis simulations are performed to achieve satisfactory performance over the operating bandwidth.
In the third step, a co-design is introduced to obtain the performance of the proposed system after the integration with antenna array elements. The co-design integrates the power amplifier circuit and the antenna s-parameter file into a single port. The antenna results transformed from one port file to a two-port S-parameters file using the two-port analysis theory. the antenna is modeled in this work for system simulations and calculation of transmission efficiency. The MATLAB program for this operation generates the Two-port representation for the antenna array elements at the operating frequencies. Next, we calculate the equivalent two-port parameters for the simulated antenna array elements. The equivalent two-port antenna models show no differences in matching characteristics with the original one-port antennas.
The fourth step is the Compensating Network (CN) design, which uses the PA load impedances and the antenna array elements impedances. Microstrip transmission lines are used to design the proposed CNs. The main purpose of the CNs design is to satisfy the PA transistor requirements with the existence of the antenna array elements. Two AIAA prototypes with CNs and conventional designs are measured in order to verify the CNs design impact. The two AIAAs operate in the range of 3.6 to 4 GHz which is a wide frequency range. Obtained results illustrate that the minimum realized gain of the proposed AIAA is more than the conventional AIAA realized gain. The excellent agreement between the results obtained using the presented methods proves the validation of the proposed analysis and theoretical investigations.
Finally, an enhanced gain broadband PA is presented to build an AIAA system for 3G/4G and 5G communications systems. The proposed PA design approach is introduced based on using an integrated diplexer to combine the bandwidths (BWs) of PAs with narrower bandwidths, along with a phase compensation network to ensure high gain flatness, constant power level, and high efficiency over the entire bandwidth. The input and output matching networks of each amplifier are individually synthesized using wideband matching network techniques. The diplexer is designed using a low-pass/high-pass topology approach. The separate amplifiers are integrated with the proposed diplexer, resulting in extended bandwidth with enhanced gain. For verification purposes, a broadband PA is designed and implemented over the frequency band 2–4 GHz. This approach results in enhanced system reliability. The proposed broadband PA achieved a satisfactory performance across the proposed frequency range.
Analysis, fabrication, and measurements are all performed for all the designs presented in the thesis. Results obtained by numerical simulation and experimental measurments are in good agreement.