The series fed antenna arrays are widely used to minimize the feeding losses. A novel method to control the coupling/admittance between the series array elements is studied. In this work, two substrate integrated waveguide (SIW) fed aperture coupled 1×4 patch arrays are designed on the LTCC platform. The admittance of the array elements are controlled with the stepped SIW and the non-uniform aperture coupling technique. The simulated and measured −10-dB impedance bandwidth of the designed antenna is approx. 6-7%. At 75 GHz, the maximum boresight directivity and realized gain of the designed antennas are 12 dB and 9 dBi, respectively. Additionally, a microstrip line (MSL)-SIW vertical transition structure is designed to facilitate the multi-layered RF structure in LTCC.
Integrated lens antennas are widely used in high gain and beam steering applications at millimeter wave frequencies. The ILA has often large height and suffers from significant scan loss. In this article, we demonstrate a low-profile, efficient, and scanloss-reduced integrated metal-lens antenna (IMLA). An IMLA is a combination of a dielectric lens and metal-plate lens. A 16-λ0 diameter IMLA is designed using the HDPE and 58 stainless steel plates to achieve the f /d of 0.69. The simulated aperture and radiation efficiency of the IMLA are 73% and 92%, respectively. At 76 GHz, the simulated and measured realized gain of the fabricated IMLA are 31.24 dBi and 31 dBi, respectively. The IMLA is designed to steer the main beam to ±30°. The scan loss is reduced by tilting the radiation pattern of the feeds at offset positions along the focal plane. The radiation pattern of the square waveguide feed is tilted using asymmetrical dielectric pins. The asymmetrical dielectric pins reduce the simulated gain scan loss of IMLA by more than 1.5 dB at 30°steering angle. The simulation results show that the inclination of the feed radiation pattern helps to limit the scan loss of the IMLA to 4.1 dB and 4.3 dB in H-and E-plane for 30°steering angle, respectively. The measured scan loss of the manufactured IMLA is 3.8 dB and 6.2 dB in H-and E-plane, respectively.
The fifth generation (5G) wireless communications systems have brought a growing need for various antennas, electrically small and large, low-gain and large-gain, also at millimeter wavelengths, and in many cases with beam steering or switching capability. Frequencies of 28 GHz, 38 GHz, 58 GHz, 60 GHz, 71-86 GHz, 140-150 GHz, and some even higher window frequencies are of interest in 5G and subsequent generations. Different parts of the systems need different kinds of antennas. In this presentation, we discuss two antenna types that we have recently studied, namely high-gain lenses with beam switching capability and lower gain printed antennas that suit very well for mass production.
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