Research On Miniaturized Multiplexer Based On GaAs Process

In order to alleviate the shortage of chip design area,Ga As IPD(integrated passive device)process can design passive devices with small size and insertion loss by virtue of its thick metal layer,such as passive circuits,filter,balun,power divider and so on.Compared with LTCC,PCB,CMOS and other processes,it has great advantages.1.For the filter in N77(3.3 ? 4.2GHz)band of communication system,a filter with high out of band rejection is designed by using Ga As IPD process.In addition to the filter communication frequency band.The process used in this thesis has three metal layers,mainly using relatively thick metal 2 layers and metal 3 layers to design n77 filter.In order to reduce the area of the filter chip,the filter structure based on capacitive coupling is adopted.At the same time,in order to reduce the band interpolation loss and improve the performance of the filter,the laminated inductor is designed by taking advantage of the thick metal layer of IPD process.Compared with the ordinary inductor,the Q value can be increased by 20% and the area can be reduced by 50%.Due to the high requirements for the out of band suppression of the filter,the series resonator is used as the zero point.In addition,by adding series inductance and capacitance to the grounded resonator,the corresponding zero points are introduced at high frequency and low frequency respectively.The n77 filter is finally designed with excellent performance.The band interpolation loss of n77 is 2.3d B,the rejection at 2.690 is 29 d B,and the rejection at 5.150 GHz is 39 d B.At the same time,it can reach-60 d B at 1.7? 1.780 GHz and S11 is better than 20 d B.2.Filter for N78(3.3 ? 4.2GHz)band of communication system.A filter with excellent performance is designed by using Ga As IPD process.Similar to the design principle of N77,the N78 filter design in this thesis also uses stacked inductors and MIM capacitors.Based on capacitive coupling and zero suppression technology,an N78 filter is designed.In N78 band,the insertion loss is less than 2.4d B,the in band return loss is less than 19 d B,and the out of band suppression at 2.690 GHz and 5.150 GHz reaches 25 d B and 40 d B respectively.The size of the filter is only 0.8mm × 1mm × 0.1mm.3.A triplexer is designed for the communication frequency band of 1.560-1.606 GHz,2.4-2.5GHz and 4.9-5.950 GHz.Multiplexer design technology is one of the indispensable components of RF front-end.Using multiplexer,multiple systems can share a common multi band antenna.It can greatly reduce the area of RF front-end.In this thesis,a triplexer is designed by using Ga As IPD process.The insertion loss of 1.560-1.606 GHz band is about 2.1d B.The insertion loss in the 2.2-2.5GHz band is about 2.1d B.The insertion loss in the 4.9-5.950 GHz band is about 1.8d B.The echoes of the three passbands are better than,18 db,19d B and 11 d B respectively.