T his paper presents a temperature compensation voltage controlled oscillator (VCO) based on Cross-Coupled pair and Colpitts structures which is suitable for military fields. Also, two inductors have been used for increasing the negative conductance. By using this method, start-up condition has been improved. Two varactors and a simple capacitor bank are applied for covering a wide tunning range. T he VCO has been designed and simulated in T SMC 0.18 µm CMOS technology.To compensate the frequency drift over a temperature range, MOS varactors are used and biased with a complementary to absolute temperature (CTAT) voltage reference. This CT AT voltage reference has been applied to two varactors and decreased the frequncy drift over temperature range. By using this technique, the proposed VCO can achieve a very stable frequency of 11.5 PPM/°C at 24.35 GHz over a temperature range of-40~120 °C. Simulation results also show the VCO covers the frequency range of 23.75~24.8 GHz. T he simulated phase noise of center frequency is-102.6 dBc/Hz at 1 MHz offset frequency. T he VCO consumes 10.4 mW DC power under 1.8 V supply voltage. The figure of merit of the VCO is-179.8 after compensating.

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This paper present, the design and simulation of the Ka to v band RF-MEMS capacitive switch. The mechanic design and analysis of the RF-MEMS switches are based on both the finite element method and the full-wave electromagnetic simulation. A double-beam switch with a high impedance short transmission line is proposed to improve RF characteristics. The electronic characteristics, of the switches including insertion and return losses in up-state position, were more than -0.11 dB and less than -23 dB , respectively and isolation on down-state position was more than -30 dB on 50 GHZ frequency. In order to make lower actuated voltage, a serpentine spring folded suspension beam and low actuated area were used so that some important issues such as life and reliability of switch were considered in design.

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