An increasing need for wider bandwidths and higher data rates makes the use of millimetre-wave frequencies (30–300 GHz) attractive for the wireless communications applications. At millimetre-wave frequencies, directive antennas with a moderate or high antenna gain are usually needed to compensate for a high free-space path loss. Directive antennas have a narrow radiation beam and therefore beam steering is required to cover a wide angular range. Other requirements for the millimetre-wave antennas are, for example, a small form factor and integrability with the radio frequency (RF) front ends. The objective of this thesis is to develop practical millimetre-wave antenna solutions for 60–110 GHz frequencies using low-cost manufacturing technologies, such as low temperature co-fired ceramic (LTCC) and printed circuit board (PCB). Investigations are done to improve the antenna performance, such as to increase the antenna gain and the operational bandwidth, and to suppress the mutual coupling between antennas. In addition to fixed-beam antennas radiating broadside or end-fire radiation beams, three beam-steering antenna demonstrators are also developed. The performance of 60 GHz patch antennas and arrays on LTCC is improved by processing air cavities inside substrate to increase antenna gain and operational bandwidth. A 60 GHz uniplanar-compact electromagnetic band-gap (UC-EBG) structure is implemented on LTCC to increase the antenna gain and reduce the mutual coupling between antennas. A dual-resonant patch antenna and a 16-element array are designed for wideband performance at W-band (75–110 GHz). To reduce the feed network losses, a 60 GHz chain antenna array with a substrate-integrated (SIW) feed network is designed on LTCC. A surface-wave assisted 60 GHz dipole and an array are designed on LTCC for end-fire radiation. A high-gain beam-switching dipole is presented for 77 GHz. A 90 GHz phased-array transmitter on LTCC is developed for providing beam steering over ±25 deg. A beam-switching dual-spherical lens antenna system is presented for the E-band (71–76 GHz). The lens has a beam-switching array with 16 Vivaldi antennas on a multilayer PCB as a feed. Beam steering between ±40 deg. is demonstrated in one dimension.
|Translated title of the contribution||Millimetriaaltoantennien suunnittelu ja toteutus LTCC- ja PCB-tekniikoilla keilankääntösovelluksiin|
|Publication status||Published - 2019|
|MoE publication type||G5 Doctoral dissertation (article)|
- millimetre wave
- phased array