Ka-band Active Phased Array Radar T/r Modules

Transmit/Receive(T/R) modules are one of the key components of the phased array radar. Its performance affects the whole performance of the phased array radar system directly. Ka-Band T/R modules are the research hotspot in our country and overseas. Based on the technology of microwave/millimeter-wave hybrid integrated circuits, the T/Rmodules with low-cost, high performance and miniaturization is presented in this paper.According to the index requirements, the whole program of Ka-Band is determined firstly. The indexes are assigned to related devices. Then the whole program is validated according to the selected components. Some passive circuits are made tentatively, but their performances are not good. Through testing, it’s very difficult that Wilkinson divider with isolation is made at Ka-Band. It can not be used because of its unbalance factor of the insertion loss. At last, the alternate MMIC is selected. Based on the technology of millimeter-wave hybrid integrated circuits, the circuit diagram of T/R modules is designed with dimensions57mm×35mm×13mm, then fabricated, assembled, debugged, and tested. The results show good meet to the design requirements. The transmitting and receiving gains are both greater than15dB, the receiving noise figure is less than3.5dB, the gain balance between the transmitting and receiving channels is less than±1dB, the gain balance between the array transmitting channels is less than±1dB, the receiving channels’ is also less than±1dB, the phase shift accuracy is less than3.5°, the isolation between the transmitting and receiving channels is greater than25dB and the isolation between the modules is greater than24dB.Chapter1is an introduction of the whole dissertation. First, dissert the characteristic and the development trend of millimeter wave simply; then, introduce the research status quo on domestic and abroad; last, briefly introduce the purpose and the main indexes.Chapter2briefly introduces the theory of passive circuit and tries to design millimeter-wave Wilkinson divider.Chapter3describes the devices (low noise amplifier, phase shifter single-pole double-throw switch, power divider) used in T/R modules, related theory and definitions; then selects related components according to the assigned indexes. Last, does the system simulation according to the principle block diagram of T/R modules to demonstrate its correctness.Chapter4is the focus of this thesis, designs the control circuit of T/R modules, does the circuit layout and designs the structure; then tests the gain, the phase shift accuracy, the gain balance and the receiving noise figure.Chapter5is the conclusion of this thesis, briefly describes the main work, then points out the design considerations of T/R modules and puts forward some improvement suggestion.