The Study And Design Of A 5-bits Ku-band Digital Phase Shifter

As a kind of microwave control circuit, phase shifter has been widely used in radar,missile,communications and other fields. Phase shifter is the key component of phased-array radar, because of this, it can be said that the rapid development of phase shifter is inseparable with the rapid development of phased-array radar. Today, phased-array radar is still the main application field of the digital phase shifter. Phased-array radar has many transmit/receive components, all of these components need a corresponding digital phase shifter. The performance of phase shifter directly affect the performance of transmit/receive components, thereby affecting the performance of phased-array radar. Therefore, the research about the topic is of great significance.First, this paper describes the basic principles of three commonly used semiconductor switch control devices. Microwave switch control device is the important part of the control circuit. Because of the advantages of small volume, fast response, small controling power etc, making semiconductor devices been widely applied. This article uses a hetero junction FET with high mobility electrons as a switch.Based on the introduction of the principle and circuit structure of various types of digital phase shifter in detail, a Ku-band 5-bits digital phase shifter is studied and designed in the paper. The step of the 5-bit digital phase shifter is 11.25°, the change of 32 phase states can be realized, the five basic states of the phase shift are 11.25°,22.5°,45°,90°and 180°. The proposed phase shifter is fabricated using loaded line type phase shifter for 11.25°and 22.5°; using hybrid-coupled reflection line type phase shifter for 45°,90°and 180°. The paper carries out the schematic design of every state of the proposed phase shifter in ADS and gives out the simulation results. After every state of the proposed phase shifter meeting the request, the schematic of the designed five status bits schematic are cascaded by the paper, forming a complete schematic of the proposed five-bits digital phase shifter, and carries out the simulation of the schematic in ADS.Finally, the layout of the proposed digital phase shifter is completed by this article. The cascade simulation results show, in the 11.7-12.2GHz frequency band, the VSWR of the phase shifter is lower than 1.4, the insertion loss is lower than 5dB, the phase error is lower than±5°. From the simulation results, we can see that the phase shifter with the performance of high phase accuracy,low insertion loss and low VSWR and so on. Every performance of the proposed phase shifter meets the requirement, verifying the correctness of the design.