NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. We have demonstrated antenna-coupled electro-optic modulators at frequencies up to 98 GHz. The antenna-coupled design allows the modulator to overcome the velocity-mismatch problem which limits the maximum operating frequency of more conventional designs. Several modulators have been demonstrated, including a prototype narrowband phase modulator (optical wavelength 0.633 [...]) at 10 GHz, a narrowband phase modulator (0.633 [...]) at 60 GHz, a broadband Mach-Zehnder modulator operated as a phase modulator at 60 GHz, and a broadband Mach-Zehnder amplitude modulator at 94 GHz (optical wavelength 1.3 [...]). The performance of the prototype modulator at 10 GHz is not quite as good as that of conventional modulators at this frequency, but is comparable. The performance of the mm-wave modulators cannot be directly compared to conventional modulators, as none exist at these frequencies. However, we have established that the relative performance of the mm-wave modulators is consistent with a simple scaling law. Linearized [...] modulators have been demonstrated recently by other workers. These linearized modulators consist of conventional [...] coupler-modulators cascaded with additional couplers. We have considered the general case of cascade-linearized [...] modulators, and have shown that it is possible to provide up to four degrees of freedom which can be used to modify the modulator transfer function. We have shown that these degrees of freedom can be identified and separated for design purposes, and have shown how to implement a given design.