Wireless interconnect between on-chip and LTCC antennas for system-in-package applications

A novel system-in-package (SiP) implementation is presented for a transmitter (TX) module which makes use of electromagnetic coupling between the TX chip and package antennas at 5.2 GHz. The TX chip is realized in 0.13 mum CMOS process and comprises an on-chip antenna. This on-chip antenna serves as the oscillatorpsilas inductor as well. The TX chip is housed in a low temperature co-fired ceramic (lTCC) package with a patch antenna. The on-chip antenna feeds the LTCC patch antenna through aperture coupling, thus negating the need for RF buffer amplifiers, matching elements, baluns, bond wires and package transmission lines. This first ever combination of onchip and LTCC antennas increases the gain of the module by 32 dB and range by 23 m with respect to the on-chip antenna alone, without deteriorating the circuit performance and power consumption.

I. Introduction

This era of miniaturized RF electronics requires innovative designs to achieve compact yet efficient wireless systems. Much of the recent RF research is focused on the System-on-Chip (SoC) and the System-in-Package (SiP) solutions [1]–[2]. In the SiP domain, LTCC can offer numerous advantages like arbitrary number of layers which can not only embed passives but can also realize vertical integration of RF modules. Moreover, the low loss nature of the LTCC substrates makes them very suitable for efficient antenna design. Recently, an RF front end has been implemented at V-band in LTCC with an integrated package antenna [3]. Though the SoC is a more size efficient approach, the on-chip antennas are usually very inefficient because of the lossy nature of the Si substrates.