Alexander Werner Hees

Ultra broadband dual polarized dipole array with metallic reflector

An ultrawideband (UWB) dual polarized dipole array with high directivity is presented. It operates in the frequency range from 2.7 GHz up to 8.5 GHz. The dipoles are shaped elliptically and are realized on an rf substrate. The two polarizations were created by four dipoles each. A microstrip to slotline transition feeds every single element. Two four-way Wilkinson divider networks split the power for each polarization which results in the same magnitude and phase at each output port. The remaining dipole in the center of the array is not used and terminated. A metallic reflector is placed 10 mm below the antenna structure to increase the directivity and to lower the backward radiation. With this design, a mean gain of 6.4 dBi and a stable main beam direction with a nearly constant 3 dB beam width, both in the E-and H-plane, were achieved. The antenna shows good time domain behavior with a sharp peak as well as low ringing of the impulse response.

Characteristics of a corrugated tapered slot antenna with dielectric rod and metallic reflector

A novel ultrawideband (UWB) tapered slot antenna with high directivity is presented. It operates in the frequency range from 2.2 GHz up to 8.5 GHz. The antenna consists of three parts. As feed, a tapered slot on a PCB is used. Additional corrugations at the lateral metallic borders of the tapered structure lead to reduced side lobe levels and a flat gain in the main direction. The PCB is inserted into a cylindrical dielectric rod to increase the directivity. Finally a metallic reflector is added at the back of the antenna structure to reduce the backward radiation. With this design, a mean gain of 9 dBi and a stable main beam direction with a nearly constant 3 dB beam width, both in the E- and H-plane, were achieved. The antenna shows excellent time domain behavior with a high and sharp peak as well as low ringing of the impulse response.

Tapered slot antenna with dielectric rod and metallic reflector

This work has developed an ultrawideband tapered slot antenna in the frequency range from 2.2 GHz to 8.5 GHz. High directivity is achieved by using a dielectric rod as a waveguide and a metallic reflector. The antenna exhibits a stable main beam direction over the band of operation and a measured mean gain of 8.1 dBi. At 5.5 GHz, a 3 dB opening angle of 42deg and a front-to-back ratio better than 14 dB were realized.