A quantum dot under an elongated gate, a so-called jellybean dot, is one of many potential solutions to realizing the long-distance dot-to-dot communication in a Si CMOS chip, which is the key to realizing universal quantum computing. Also, in NISQ era, the jellybean dot may provide other aspects for understanding the quantum behaviors and simulating quantum systems. This thesis is a summary of the achievements of the jellybean dot project. In addition to the fundamentals of the qubit physics and architectures, the thesis contains three main parts: a) The development of the low-damage, high-precision fabrication process for jellybean chip; b) The tests and measurements of the fabricated jellybean qubit device; c) The development of the off-chip antenna for coherent control of the jellybean chip. For the first part of the thesis, a low-damage high-precision fabrication process has been developed for realizing the jellybean dot with other functional peripheral components, such as the SET for sensing and the confinement barriers. The process recipe can reach a resolution of ≈25 nm feature length of the gates with a relatively low dose of electron radiation. Using this fabrication process, a batch of jellybean quantum chips has been successfully fabricated. One of them was then transferred to a dilution refrigerator for further measurement. For the second part, measurement of the jellybean-type quantum dot was carried out in cryogenic equipment to characterize the fabricated chip and measure the chip’s quantum performance. At low electron occupancies where disorder effects and strong electron-electron interaction dominate over the electrostatic confinement potential, the measurement data reveals the formation of three coupled dots, akin to a tunable, artificial molecule. One dot is formed centrally under the gate and two are formed at the edges. At high electron occupancies, these dots merge into one large dot with well-defined spin states, verifying that jellybean dots have the potential to be used as qubit couplers in future quantum computing architectures. For the last part, an SRR-based off-chip PCB antenna has been developed for spin control. This off-chip antenna is even more critical when there are more and more dots and fan-out gates within a single quantum chip. The measurement results show that the resonance features of such an antenna match the simulation, suggesting that the designed antenna has strong potential to realize off-chip spin control.