Optimize design to observe high gain oscillation at 10 GHz Implement the mixing operation to the oscillator to make it a self-

oscillating mixer

Fabricate and obtain experimental data of the push-pull amplifier and self-oscillating mixer using FR4 substrate specifications

Correlate between the simulations and the experimental data Optimize design to increase the gain and output power signal while

reducing the noise at other frequencies even more Implement the phase locking (PL) and phase locked loop(PLL)

operations to the self-oscillating mixer to create an injection locking phase-locked loop self-oscillating mixer

Olaniyi Jinadu, Dewakar Madapuci Kanday, Prof. Afshin DaryoushElectrical and Computer Engineering Department, Drexel University, Philadelphia, Pennsylvania 19104, USA

Advantages of Self-Oscillating Mixers

A Push-pull Self Oscillating Mixer Design Based On Foundry Services

Circuit schematic using Agilent ADS

Potential for oscillation at 5 GHz and Harmonic Content

Introduction

Conclusion

Microwave local oscillators (LO) are used for frequency translation from baseband/intermediate frequency (IF) to radio frequency (RF) signals using mixers.

The concept of self-oscillating mixers (SOM) is very attractive to achieve high dynamic range and conversion efficiency in mixers by combining both oscillation conditions in circuits and nonlinear mixing.

Self-oscillating mixer eliminates the need for a buffer amplifier that has to be used after conventional mixers.

Demonstrated the design and implementation of both differential amplifier and differential oscillator

Band-stop filter was modeled at resonance frequency of 5 GHz The performance of the differential oscillator (gain) was observed as

the oscillator should oscillate at 10 GHz with a gain of at least 3 dB

Si-Ge/Si HBT device parameters from IBM and Si CMOS technology from TSMC are considered to implement the SOM at 10 GHz for mixing with IF/RF signals.

The foundry parameters are employed to plot transistor DC I-V device and design load lines for appropriate operation point.

The push-pull amplifier is designed for operation in class AB as a building block of oscillator.

The source current of push-pull amplifier is used for mixing of IF and LO signals to generate RF.

Design Procedure

Pick best operation

point for low noise and gain

Design a differential amplifier

Add resonant circuit and build positive feedback oscillator

Tune oscillation frequency

Provide IF/RF for self-oscillation

mixing

The self-oscillating mixer is a combination of both the oscillating and mixing circuit functions required in independent blocks of an oscillator and mixer.

A push-pull circuit topology will result in a lower power consumption oscillator and more efficient mixing functions.

Using an external frequency reference or using a self injection locking, frequency of the local oscillator is stabilized

The stabilized source of 10GHz is used for realization of clock reference in distributed systems.

In order to make the oscillator portion frequency and phase stabilized, self forced oscillation (e.g. dual self-injection locked and phase locked loops) can be used

Push-Pull Self-Oscillating Oscillator

Differential Operation: Vin2 – Vin1 = V1

A resonant circuit at 5GHz is designed using a band-stop filter and provides positive feedback between based and collector separate transistor pairs to build oscillator at 5GHz and use 2nd harmonic generation at 10GHz

Future Design Modifications

Amplifier Gain: Output Power (dB) – Input Power (dB)

Oscillator circuit schematic using Agilent ADS

Oscillator Gain at oscillation frequency

Band-stop filter schematic for 5GHz

Insertion gain at 5 GHz with insertion loss at 10GHz

Differential Amplifier: ADS Modeling

Differential Amplifier Circuit

RF in

RFout