A s i n g l e chip, M M I C v e c t o r modulator designed f o r u s e i n a n X band p h a s e d a r r a y r a d a r s y s t e m i s d e s c r i b e d . The d e s i g n p r i n c i p l e i s c a p a b l e of a d d r e s s i n g o c t a v e b a n d w i d t h s and f r e q u e n c i e s up i n t o t h e mm wave region. The c i r c u i t i s novel i n t h a t i t i s purely p a s s i v e , using unpowered FETs as t h e c o n t r o l e l e m e n t s . I t i s t h e r e f o r e l o w n o i s e and expected t o be capable of handling r e l a t i v e l y l a r g e RF s i g n a l l e v e l s of up t o 1 W . Analogue c o n t r o l of t h e v e c t o r e x t e n d s over a range of more t h a n 30 dB f o r a m p l i t u d e and o v e r 0-360 d e g r e e s f o r phase.Swept frequency, measured phase e r r o r s a r e l o w e r t h a n + / -l o d e g f o r a 10% i n s t a n t a n e o u s bandwidth anywhere i n X-band (8-12GHz).

A radio frequency identification (RFID

A 6-bit, digitally controlled phase shifter is described. Details of the design, manufacture and measured results are presented . The single chip Monolithic Microwave Integrated Circuit (MMIC) covers the 4.9 -5.7GHz band with an rms phase error of 5.5@. If instead of assuming ideal binary weighted bits, the most appropriate phase states are selected then the control of the chip is optimised. This results in an optimised rms phase error of 1.9°. Extremely low levels of insertion loss variation with phase state make this chip particularly useful for Synthetic Aperture Radar (SAR) applications.

A Monolithic Microwave Integrated Circuit (MMIC) based gain and phase control module for use in Beam Forming Networks (BFNs) is detailed. Gain and phase are digitally controlled with 25dB of gain control range, 360°phase control range, 5 bit resolution and net gain. The module uses numerical redundancy to achieve tolerance to bit weight errors and operates over the 10.7 -12.75GHz satellite telecommunications band. Each module has a single RF input and dual outputs to control two elements of a BFN independently. The module contains a CMOS Application Specific Integrated Circuit (ASIC) which generates the digital control signals and allows compensation of gain with temperature. All level shifters to interface between the ASIC and the MMICs are also included as an integral part of the module