Radio receivers are part of our day to day life. These are the electronic devices which are receptors of radio waves and translate the obtained information in an acceptable form. They are utilized in combination with antenna. The main purpose of antenna is to convert radio waves into electrical form and required information is extracted by receivers. Filters are also necessary in receivers which are used for separating the radio frequency signals from other signals picked up antenna and electronic amplifier is used to raise power of signal for further processing and finally desired information is recovered using demodulation process. FM radio is one of the most common application. Although there are number of wide range receivers available in the present world but as per customer requirement it becomes necessary to have a single receiver compatible with multi-standards taking care of multi-standard requirements where GSM, DECT, CDMA are one of the most common standards. So, if a receiver is compatible with multiple standards a lot of power and time will be saved while defining a single receiver operating at multi-standards rather than defining multiple receivers.
Mixers are one of key building blocks of trans-receivers circuitry whose main aim is to convert the frequency of signal i.e. lower to higher known as up-conversion and higher to lower is known as down-conversion. Up-conversion process takes place in transmitter circuitry whereas down-conversion takes place in receiver circuitry. They can be categorizes into several types but the Active mixers are most widely used due to high performance features as compared to other types. The performance of mixers plays a major role while determining the performance of receivers. This is dependent on number of parameters like noise figure, Conversion gain, Linearity.
This work proposes a novel mixer operating at multi-standards based on Active Mixer topology. The design provides low noise and high performance in terms of conversion gain and moderate linearity performance. The design has been simulated in Cadence Virtuoso which shows good results while tested at 7 frequencies within a band of 50Hz to 15GHz overcoming the problem of image rejection as well. The design will be sent to foundry for fabrication and testing will also be done at later stage.
This novel design will be a boon to the researchers working in the field of multi-standard receivers as mixers are most non-linear and noisy blocks and simultaneous testing at 7 frequencies is not done yet.