Abstract: A miniature vertically polarized multi-frequency antenna 10 is embedded in a substrate 11 and suitable for use within a wireless device. The antenna 10 includes a first lateral member 14 and a second lateral member 16, which is spaced from and parallel to the first lateral member 14. The antenna 10 has a wide tuning range due to multiple resonances provided by the lateral members 14, 16. The antenna 10 is shortened by reactive loading and by embedding the antenna in material having a high dielectric constant. Tuning circuits 30, 32 are coupled to respective ends of one of the lateral members 14, 16. The tuning circuits are located on a common plane with the lateral member to which they are connected. The tuning circuits 30, 32 electronically add reactance to the antenna to alter the frequency at which it resonates.

Abstract: A resonant circuit includes a transmission line in parallel with a varactor diode. The varactor diode has a capacitance that is variable in response to an applied voltage, which allows for real time impedance matching, attenuation control, and/or compensation for tolerances of other components. The resonant circuit is used with a quarter wavelength transmission line to provide impedance transformation and matching between multiple ports. A high frequency switch provides low current consumption, improved impedance matching, relatively low insertion losses, and excellent isolation between ports.

Abstract: A miniature vertically polarized multi-frequency antenna 10 is embedded in a substrate 11 and suitable for use within a wireless device. The antenna 10 includes a first lateral member 14 and a second lateral member 16, which is spaced from and parallel to the first lateral member 14. The antenna 10 has a wide tuning range due to multiple resonances provided by the lateral members 14, 16. The antenna 10 is shortened by reactive loading and by embedding the antenna in material having a high dielectric constant. Tuning circuits 30, 32 are coupled to respective ends of one of the lateral members 14, 16. The tuning circuits are located on a common plane with the lateral member to which they are connected. The tuning circuits 30, 32 electronically add reactance to the antenna to alter the frequency at which it resonates.

Abstract: A resonant circuit includes a transmission line in parallel with a varactor diode. The varactor diode has a capacitance that is variable in response to an applied voltage, which allows for real time impedance matching, attenuation control, and/or compensation for tolerances of other components. The resonant circuit is used with a quarter wavelength transmission line to provide impedance transformation and matching between multiple ports. A high frequency switch provides low current consumption, improved impedance matching, relatively low insertion losses, and excellent isolation between ports.