• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.7 no.3
• /
• pp.492-498
• /
• 2003

In this paper, We analyze the optimum bias conditions of cascode coupled microwave mixer for maximum conversion gain mixer. Microwave self-oscillating mixer by two GaAs MESFET cascode coupled, to upper GaAs MESFET operating as a oscillator with high Q dielectric resonator and the lower GaAs MESFET operated as a mixer with low noise and high conversion characteristics. As a result of experiments, cascode coupled microwave self oscillating mixer according to optimun bias shows an 5.92 dBm oscillating power, -132.0dBc/Hz @ 100KHz at 5.15GHz and 3dB conversion loss.

• 한국ITS학회:학술대회논문집
• /
• 2002.11a
• /
• pp.138-140
• /
• 2002

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.14 no.5
• /
• pp.472-478
• /
• 2003

In this paper, a near zero If mixer was designed in cascode structure by using two single-gate FETs. Since it is driven by the second order harmonic of LO signal, a sub-harmonic cascode FET mixer has good LO-RF port isolation characteristic. In order to solve DC offset of a homodyne system, near zero If is used instead of zero If and the mixer is driven by sub-harmonic of LO signal. As RF input power was -30 dBm and LO power was 6 dBm, the designed mixer had 6.7 dB conversion gain, 8.4 dB noise figure, 31.5 dB LO-RF port isolation, -1.9 dBm lIP3 and -2.8 dBm IIP2.

• Journal of the Institute of Electronics Engineers of Korea TC
• /
• v.42 no.5 s.335
• /
• pp.55-60
• /
• 2005

A V-band MIMIC quadruple subharmonic mixer is reported in this paper. The cascode harmonic generator is proposed for a high conversion gain. The proposed cascode harmonic generator is shown with a 4-th harmonic output characteristic that represents an average of 2.9 dB and a maximum of 4 dB higher than the conventional multiplier. The measured result of the subharmonic mixer has a conversion gain of 3_4 dB which a good conversion gain at a LO power of 13 dBm. Isolations of LO-to-IF and LO-to-RF were obtained -53.6 dB and -46.2 dB, respectively. The conversion gain of the subharmonic mixer in this study has a higher conversion gain compared with some other reports in millimeter-wave range.

• Proceedings of the IEEK Conference
• /
• 2001.06a
• /
• pp.429-432
• /
• 2001

본 논문에서는 Cascode FETs 구조를 능동필터로 동작시켜 이미지제거 특성을 분석하였으며, Cascode형 자기발진 믹서를 설계하였다. Ku-band 대역에서 모의실험 결과 Cas code FETs형 자기발진믹서에서 이미지성분이 -254Bc 개선되었으며, Single FET형 자기발진믹서와 비교해서 -23dBc 이상 개선됨을 확인할 수 있었다.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.18 no.6
• /
• pp.127-132
• /
• 2018

In this paper, a high conversion gain cascode mixer was designed in W-band and verified by the fabrication and measurements. In the high frequency band such as a W-band, the conversion loss of a mixer is increased because of the poor performance of transistors. This high conversion loss of the mixer requires additional circuits which can give an extra gain such as an RF buffer amplifier, and this can affects the linearity and stability of the overall systems. Therefore, it is necessary to maximize the conversion gain of the mixer. To maximize the conversion gain of the mixer, biases of the transistor were optimized, and output load impedance was optimized by the load-pull simulations. The designed mixer was fabricated in $0.1-{\mu}m$ GaAs pHEMT technology and verified by the measurements. The measurement results shows a maximum conversion gain of -4.7 dB at W-band and an input 1-dB compression point of 2.5 dBm.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.44 no.9
• /
• pp.25-33
• /
• 2007

In this paper, the high isolation and wideband 94 GHz MIMIC(Millimeter-wave Monolithic Integrated Circuit) single balanced cascode mixer was designed and fabricated. Also, we designed and fabricated a 3 dB tandem coupler which has a high isolation and wideband characteristic. The single balanced resistive mixer which does not require an external IF balun was designed using the 0.1 ${\mu}m$ InGaAs/InAlAs/GaAs metamorphic HEMT(High Electron Mobility Transistor). The DC characteristics of MHEMT's are 665 mA/mm of drain current density, 691 mS/mm of maximum transconductance. The current gain cut-off frequency($f_T$) is 189 GHz and the maximum oscillation frequency($f_{max}$) is 334 GHz. A 94 GHz single balanced cascode mixer was fabricated using our 0.1 ${\mu}m$ MHEMT MIMIC process. From the measurements, the fabricated couplers showed wideband characteristics. The conversion loss of single balanced cascode mixer was 9.8 dB at an LO power of 10.9 dBm. The LO to RF isolation of single balanced cascode mixer was 29.5 dB at 94 GHz. We obtained in this study a higher LO-RF isolation compared to some other single balanced mixers.

• 한국정보통신설비학회:학술대회논문집
• /
• 2009.08a
• /
• pp.305-308
• /
• 2009

This paper presents the design and analysis of RF Front End for Wireless Heartbeat measurement System. In this work LNA, an inductor connected at the gate of the cascode transistor and capacitive cross-coupling are strategically combined to reduce the noise and the nonlinearity influences of the cascode transistors in a differential LNA. The Mixer is implemented by using the Gilbert-type configuration, cross pmos injection technique and the resonating technique for the tail capacitance. The resulting LNA achieves 1.26 dB NF, better than 1.88dB NF Typical Also Mixer resulting achieves 9.8dB at 100KHz.

• Journal of Advanced Navigation Technology
• /
• v.10 no.2
• /
• pp.138-144
• /
• 2006

In this paper, dual mode FET mixer for WiBro and wireless LAN(WLAN) applications has been designed in the form of dual gate FET mixer by using the cascode structure of two single gate pHEMTs. The designed dual gate mixer has been optimized to have variable conversion gain for WiBro and WLAN applications in order to save dc power consumption. The LO to RF isolation of the designed mixer is more than 20dB from 2.3GHz to 2.5GHz band. With the LO power of 0dBm and RF power of -50dBm, the mixer shows 15dB conversion gain. When RF power increases from -50dBm to -20dBm, the conversion gain decreases to -2dB from 15dB with bias change. The variable conversion gain has several advantages. It can reduce the high dynamic range requirement of AGC burden at IF stage. Also, it can save the dc power dissipation of mixer up to 90%.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.1
• /
• pp.29-36
• /
• 2009

In this paper, the design and implementation of LNA and down-mixer using 90 nm CMOS process are presented for 60 GHz band WPAN receiver. In order to extract characteristics of the transistor used to design each elements under the optimum bias conditions, the S-parameter of the manufactured cascode topology was measured and the effect of the RF pad was removed. Measured results of 3-stages cascode type LNA the gain of 25 dB and noise figure of 7 dB. Balanced type down-mixer with a balun at LO input port shows the conversion gain of 12.5 dB within IF frequency($8.5{\sim}11.5\;GHz$) and input PldB of -7 dBm. The size and power consumption of LNA and down-mixer are $0.8{\times}0.6\;mm^2$, 43 mW and $0.85{\times}0.85\;mm^2$, 1.2 mW, respectively.