The Design of a Sub-Harmonic Dual-Gate FET Mixer |
Jeongpyo Kim1, Hyok Lee1, Jaehoon Park2 |
1Dept. of Electrical and Computer Eng., Hanyang Univ. 2Div. of Electrical and Computer Eng., Hanyang Univ. |
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Abstract |
In this paper, a sub-harmonic dual-gate FET mixer is suggested to improve the isolation characteristic between LO and RF ports of an unbalanced mixer. The mixer was designed by using single-gate FET cascode structure and driven by the second harmonic component of LO signal. A dual-gate FET mixer has good isolation characteristic since RF and LO signals are injected into gatel and gate2, respectively. In addition, the isolation characteristic of a sub-harmonic mixer is better than that of a fundamental mixer due to the large frequency separation between the LO and RF frequencies. As RF power was -30 ㏈m and LO power was 0 ㏈m, the designed mixer yielded the -47.17 ㏈m LO-to-RF leakage power level, 10 ㏈ conversion gain, -2.5 ㏈m OIP3, -12.5 ㏈m IIP3 and -1 ㏈m 1 ㏈ gain compression point. Since the LO-to-RF leakage power level of the designed mixer is as good as that of a double-balanced mixer, the sub-harmonic dual-gate FET mixer can be utilized instead. |
Key words:
Dual-gate FET Mixer, Sub-harmonic Mixer, LO-to-RF Isolation |
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