Full-band direct-conversion receiver with enhanced port isolation and I/Q phase balance using microwave photonic I/Q mixer (Invited Paper)

Abstract

A full-band direct-conversion receiver using a microwave photonic in-phase and quadrature (I/Q) mixer is proposed and experimentally evaluated in terms of radio frequency (RF) range, port isolation, phase imbalance, conversion gain, noise figure, spurious-free dynamic range, and error vector magnitude. The proposed microwave photonic I/Q mixer shows significant advantages in local oscillator leakage and I/Q phase imbalance over entire RF bands, which are recognized as major drawbacks of conventional direct-conversion receivers.OCIS The growing use of the radio spectrum requires electronic systems to operate at extended radio-frequency (RF) bands and signal bandwidth, putting forward great challenges to the RF receiver design. Microwave photonic techniques are recently introduced to overcome these limitations due to several inherent advantages, such as potential full-band operation, large instantaneous bandwidth, high RF isolation, low-loss transmission, and electromagnetic interference immunity [1][2][3] . As for frequency conversion that is a crucial function in an RF receiver, several microwave photonic schemes have been studied. A photonic method for wideband tunable RF conversion was presented by Harris Corporation [4] . With different photodetection fashions, a reconfigurable photonic microwave mixer was proposed [5]

Photonics-Based Microwave Image-Reject Mixer

“…Phase-cancellation technique is another way to realize photonics-based microwave IRMs [18][19][20][21][22][23][24][25][26][27][28][29][30], also known as Hartley architecture. Figure 5 shows the principle method.…”

“…The third class of photonic IRMs based on phase cancellation applies a 90 • optical hybrid to introduce a quadrature phase [25][26][27][28][29]. Benefiting from a simple structure and the small phase imbalance of the commercially available optical hybrid over a wide frequency range, a high image rejection ratio can be achieved in a large bandwidth.…”

“…One branch is modulated by an RF signal and the other is modulated by an LO signal, both with carrier-suppressed single-sideband (CS-SSB) modulation. The CS-SSB modulation can be realized by using either optical filters placed in each branch [25][26][27], or I/Q modulators operated at CS-SSB mode [28,29]. Signals from the two branches are sent to the signal port and the LO port of the 90 • optical hybrid, which typically has two in-phase output and two quadrature output ports.…”

“…It should be noted that if other outputs of the 90 • optical hybrid are directed to PDs, single-ended and balanced mixers can also be realized. Since parallel modulations, and/or parallel filterings, and parallel amplifications are required to obtain the independent RF and LO sidebands, the system performance will therefore be vulnerable to any path length difference between the two branches [26][27][28][29]. Therefore, environmental vibration, which cause path length variations, would be a challenge for practical application of such IRMs.…”

“…In this paper, we review recent developments in photonics-based microwave IRM with an emphasis on the pre-filtering method [12][13][14][15][16][17] and the phase cancellation method [18][19][20][21][22][23][24][25][26][27][28][29][30]. Applications of photonics-based microwave IRMs in electronic warfare, radars, satellite communications, and so on, are described [31][32][33][34][35][36][37][38][39][40][41][42][43], with challenges in implementing photonics-based microwave IRMs to meet the requirements of RF systems.…”