Research And Design Of Microstrip Filtering Power Divider

As important passive components of the radio frequency front-end,Filters and power dividers are used for frequency selection and power distribution or combination respectively.In order to achieve signal filtering,the traditional method is to connect the filter in series behind the power divider.The cost is to increase the circuit size and the loss of the interconnection impedance mismatch in the integration,which makes the production cost high and the loss high.The filtering power divider integrates filtering performance and power divider characteristics to solve the disadvantages of high loss and large size in the radio frequency circuit and adapts to the needs of integration,miniaturization,and excellent performance.It can be applied in the array antenna to provide multiple input and output channels and realize the frequency selection function,which greatly reduces the production cost and loss of the antenna system.It also plays an important role in radio frequency circuits such as frequency multipliers.Based on the theory of filters and power dividers,the filtering power dividers with single passband and double passband responses are studied and designed in this paper.The main work is as follows:(1)An ultra-wideband filtering power divider is designed.The multimode resonator generates multiple resonance points in the band.By adjusting the relevant branches,these resonance points are evenly distributed in the passband to obtain ultra-wideband characteristics.The loaded inner ring is used to control the position of the transmission zeros to improve the selectivity of the passband.The actual measurement results show that the relative bandwidth of the structure is 106%,and its rectangular coefficient is about 1.08.It has the characteristics of ultra-wideband and high selectivity.Based on the ultra-wideband filtering power divider,a filtering power divider with notch band is designed to remove interference signals.Half-wavelength stepped impedance open stub and spur line form notch bands with center frequencies at 5.8 GHz and 8.2 GHz,respectively,which eliminates the interference of WIFI and satellite communication frequency bands.The test proves the correctness of the design and has the advantages of high selectivity,and anti-interference.(2)A filtering power divider with phase shift output is designed.The filter based on signal-interference technology replaces the 1/4 wavelength transmission line of the traditional power divider.The stepped impedance open stub achieves a fixed phase difference between the two output ports.The relative bandwidth is 32.7%,and the phase shift value is maintained at 30°(+-)5° within the bandwidth.This structure integrates phase shifting,filtering and power divider.(3)A high-selectivity dual-band filtering power divider based on SIR is designed.The SIR resonator generates 4 resonance points,which are combined in pairs to form upper and lower passbands.one 1/4 wavelength open stub and an improved CSRR structure are used to achieve 4 transmission zeros,which improves the selectivity of the two passbands.The two frequency bands include 1.8 GHz-2.2 GHz,and 3.4 GHz-3.6 GHz are suitable for 5G communication applications.This structure uses only one resonator to achieve a dual-band filtering power divider,which has the advantages of high selectivity,multiple functions,and a small number of resonators.