60 GHz SoP transmitter integrating sub-harmonic frequency ASK modulator

Abstract

This thesis proposes a simple transmitter structure at 60GHz, and implements it fully integrating all necessary functions in LTCC SoP(System On a Package). The presented transmitter SoP integrates an antenna, modulator, and oscillator in it with the dimension of 26$\times$18$\times$0.6 $mm^{3}$. The proposed transmitter structure uses ASK modulation at sub harmonic frequency (30Ghz), and multiplies the modulated signal to 60GHz band. By using this structure, the modulator can be implemented at a relatively lower frequency, and the tx mmic amplifiers are replaced with just one frequency multiplier mmic. Therefore the total number of mmics for the transmitter is reduced, and cost effective transmitter package is possible. The measurement results verify that the sub harmonic modulation structure is suitable for the high data transmission at 60GHz. The internal functional block consists of oscillator, attenuator, modulator, coupler, frequency multiplier, transition, and antenna. Commercial mmics are used for frequency multiplier, oscillator, and attenuator. Beside them, the antenna, transition, coupler, modulator, and resonator for the oscillator mmic are designed and measured in this thesis. A simultaneously on/off matched reflection type ASK modulator with high on/off ratio is proposed. The modulator uses conventional rat race and two shottky diodes and functions as a switch. The matching procedure for the switch on and off state simultaneously is derived and proposed. With the matching procedure, the influence of the harmonic generated by the diode on the impedance at fundamental frequency is studied, and used for the design of modulator. The measured on/off ratio is more than 30dB. Two layer of LTCC is used for the modulator, and the size is about 11$\times$11$\times$0.2$mm^{3}$. Beside the conventional rat race, the SMD type of multi layer misalign insensitive Machand balun is proposed as well The oscillator mmic chosen for this thesis needs external ...