Yuanfeng She

LTCC Oversized Rectangular Waveguide Slot Array Antenna With Air-Layer in the Radiating Part in the Millimeter-Wave Band

This paper presents an LTCC oversized rectangular waveguide slot array antenna with an air layer in the radiating part. The antenna is fed by an LTCC fully-filled waveguide. The air-layer addition reduces the transmission loss to enhance the gain. It also reduces the effective dielectric constant to enhance the bandwidth of the series-fed slot array. The measured near-field distribution shows the hard-surface sidewalls to enhance the field uniformity on the aperture by ensuring quasi-TEM mode propagation. The transmission loss in the radiating part with the addition of the air layer of half the height was reduced compared with conventional fully-filled LTCC antenna.

Loss evaluation of post-wall waveguides and its effect on antenna efficiency in millimeter-wave bands

Loss evaluation has been done on various transmission lines for the purpose of a precise antenna design in millimeter-wave bands. The transmission losses have been estimated per unit length by measuring the losses of microstrip lines and post-wall waveguides on substrates with different thickness in different wavebands. Compared the experimental losses with the simulated results, the frequency dependence of the effective conductivity and the complex permittivity obtained by a whispering gallery mode resonator method are quantitatively confirmed. The effects of the transmission loss on the antenna efficiency as well as other loss factors are discussed by measurements with different sizes of post-wall waveguide-fed parallel plate slot arrays.

Loss reduction by air-region insertion to rectangular waveguide-fed oversized post-wall waveguide slot array antenna in the millimeter-wave band

In this paper, loss estimation in each part of the rectangular waveguide fed oversized post-wall waveguide-slot array antenna with the air layer is presented. The air-layer insertion reduces the transmission loss to enhance the antenna gain. We have reduced the dielectric loss in the radiating part from 3.5 dB for the fully-filled antenna to 0.5 dB for the partially-filled antenna. Similarly to insert the air-layer in the feed waveguide, transmission loss of the feeding part can be reduced by about 1/6. A new T-junction model with circular patches for reflection canceling is introduced and deigned in the 60GHz band.

Millimeter-wave transmission-loss evaluation of microstrip lines and post-wall waveguides and effects on efficiency of post-wall waveguide slot arrays

In this paper, the authors have obtained the transmission losses by measuring microstrip lines and post-wall waveguides of different lengths and estimated the loss per unit length. These losses have been analytically derived by different closed formulas and compared with the measured values. The effective conductivity and complex permittivity by WG mode resonator method have been quantitatively confirmed in millimeter wavebands. The efficiency due to the transmission loss has been discussed.

Loss reduction & bandwidth enhancement by air-region insertion to LTCC rectangular-waveguide slot arrays in the millimeter-wave band

This paper introduces a LTCC single-mode waveguide of εr=6.6 and tanδ=0.013 inserting air region in the half along the height to reduce the transmission loss and the effective dielectric constant. The transmission loss of the waveguide has been reduced to 1/6. The total gain is enhanced by 8dB and the 3dB bandwidth is also been increased from 1.3GHz to 2.3GHz in a 12-element slot array antenna in the 60GHz band.