Design And Implementation Of Reconfigurable Microstrip Power Divider

The fast development of modern wireless communication technology poses strict requirements on the communication ability of the equipment.From the aspect of further enhancing the communication performance,many electromagnetic problems should not only focus on the performance of individual module.It is more reasonable to study them from the perspective of the entire system.Phased array radar technology has made great progress in recent years,in which the power divider(PD),acted as one of the most important devices of the RF front-end,has been widely used in the design of power amplification systems and phased-array feed networks.Therefore,the research on the design of power divider is of great significance and has promising prospects of practical applications.Currently the traditional power divider with single working frequency and single power dividing ratio can no longer meet the requirement of the rapid development of modern reconfigurable antenna array technology.Due to the potential advantages such as reusability,tunability,and flexibility,the reconfigurable power divider can readily satisfy the requirement of different working frequencies and power dividing ratios,and is able to realize the functionalities that is originally achieved by multiple power dividers.Moreover,it can even control the beam of the antenna array in real time.Thus,the reconfigurable power divider has attracted considerable attention in recent years.Aiming at designing power dividers with different operating frequency and different dividing ratios,this dissertation mainly studied the reconfigurable technology of power dividers from the following two aspects,i.e.,reconfigurable operating frequency and reconfigurable power dividing ratio,specially,the main contribution of the thesis is summarized as follows:.Firstly,to deal with the challenges of designing the high power ratio of microstrip power dividers,two efficient solutions are put forward.The first scheme utilizes ?-type branched and defected ground structures to realize low characteristic impedance and high characteristic impedance microstrip transmission lines,respectively.Based on the equivalent model analysis,a T-shaped unequal power divider with high power dividing ratio is proposed,which achieves a dividing ratio of 9:1.The second scheme analyzes the input impedance and the tunable characteristics of parallel coupled lines loaded with varactors using the transmission line theory,on the basis of which,a frequency reconfigurable power divider with a dividing ratio of 10:1 is proposed,which achieves a continuous tuning range from 0.78 GHz to 1.2GHz.The power dividers mentioned above are simulated and measured.The results show that the measured results are in good agreement with the simulation results.Secondly,the stub structures loaded with varactors are introduced to construct a dividing ratio reconfigurable power divider by controlling the reverse voltage of varactors.And a reconfigurable power divider with a continuous dividing ratio from 2:1 to 100:1 is achieved.A prototype of the power divider is fabricated.The measured results are consistent with the simulation results and the theoretical analysis.Finally,a new reconfigurable power divider with tunable operating frequency and dividing ratio is presented to overcome the deficiency that the above mentioned dividing ratio reconfigurable power divider can only work at a single operating frequency.The proposed power divider utilizes a pair of phase shift circuits to realize the reconfigurable characteristics of operating frequency and dividing ratio.Besides,a prototype with a frequency range from1 GHz to 2GHz as well as a dividing ratio range from 2:1 to 20:1 is fabricated,and the measured results agree well with the theoretical derivation and simulation results.