Novel microwave filter technologies are of great importance in the development of modern communication systems. In a typical communications system, filters block unwanted frequencies and should have small attenuation in the desired channel.To achieve this, filters need to have low loss, high selectivity and high Q. In addition, miniaturization is another factor for modern systems. In this talk we will discuss some filter technologies developed in our group, which include Metamaterials, High Temperature Superconductors and Balanced configurations.