| 摘要 |
A quadrifilar antenna is comprised of four radiators which, in the preferred embodiment, are etched onto a radiator portion of a microstrip substrate. The microstrip substrate is formed into a cylindrical shape such that the radiators are helically wound. Also etched onto the microstrip substrate is a feed network that provides 0.degree., 90.degree., 180.degree. and 270.degree. signals to the antenna radiators. The feed network utilizes a combination of one or more branch line couplers and one or more power dividers to accept an input signal from a transmitter and to provide therefrom the 0.degree., 90.degree., 180.degree. and 270.degree. signals needed to drive the antenna. For receive operations, thefeed network utilizes these same components to receive the 0.degree., 90.degree., 180.degree. and 270.degree. signals from the antenna radiators and to provide a single output signal to a communications receiver. The power divider accepts an input signal and provides therefrom two output signals differing from each other in phase by 180.degree.. The branch line coupler accepts an input signal and provides therefrom two output signals differing from one another in phase by 90.degree..
|
