Abstract: An artificial anisotropic dielectric material is used as a microstrip patch antenna substrate and can achieve dramatic antenna weight reduction. The artificial dielectric is comprised of a periodic structure of low and high permittivity layers. The net effective dielectric constant in the plane parallel to the layers is engineered to be any desired value between the permittivities of the constituent layers. These layers are oriented vertically below the patch to support electric fields consistent with desired resonant modes. Substrates may be engineered for both linearly and circularly polarized patch antennas. Substrate weights can be reduced by factors of from 6 to 30 times using different types of high permittivity layers. This concept has numerous applications in electrically small and lightweight antenna elements, as well as in resonators, microwave lenses, and other electromagnetic devices.

Abstract: A patch antenna is provided with one or more tuning strips spaced therefrom and RF switches to connect or block RF currents therebetween. When a conducting path for RF current is connected between the tuning strips and the patch, the tuning strips increase the effective length of the patch and lower the antenna's resonant frequency, thereby allowing the antenna to be frequency tuned electrically over a relatively broadband of frequencies. If the tuning strips are connected to the patch in other than a symmetrical pattern, the antenna pattern of the antenna can be changed. A feed network couples RF to the antenna and includes two hybrid couplers, one for providing the correct amplitude and phase of excitation at the feed probes, and the second for effectively dissipating reflected power due to antenna impedance mismatch.